License cleanup: add SPDX license identifier to uapi header files with a license

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be.  This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier.  The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

   NOTE! This copyright does *not* cover user programs that use kernel
   services by normal system calls - this is merely considered normal use
   of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license complianc...

arch/alpha/include/uapi/asm/poll.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #include <asm-generic/poll.h>

arch/arc/include/uapi/asm/byteorder.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/cachectl.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/elf.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/page.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/ptrace.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/sigcontext.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/signal.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/swab.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arc/include/uapi/asm/unistd.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
  *

arch/arm/include/uapi/asm/kvm.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
  * Author: Christoffer Dall <c.dall@virtualopensystems.com>

arch/arm/include/uapi/asm/posix_types.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  *  arch/arm/include/asm/posix_types.h
  *

arch/arm/include/uapi/asm/ptrace.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  *  arch/arm/include/asm/ptrace.h
  *

arch/arm/include/uapi/asm/setup.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  *  linux/include/asm/setup.h
  *

arch/arm/include/uapi/asm/unistd.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  *  arch/arm/include/asm/unistd.h
  *

arch/arm64/include/uapi/asm/auxvec.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 ARM Ltd.
  *

arch/arm64/include/uapi/asm/bitsperlong.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 ARM Ltd.
  *

arch/arm64/include/uapi/asm/byteorder.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 ARM Ltd.
  *

arch/arm64/include/uapi/asm/fcntl.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 ARM Ltd.
  *

arch/arm64/include/uapi/asm/hwcap.h

+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 /*
  * Copyright (C) 2012 ARM Ltd.
  *