commit 791c13b7 upstream.

Undefined rproc_ops .kick method in remoteproc driver will result in
"Unable to handle kernel NULL pointer dereference" in rproc_virtio_notify,
after firmware loading if:

 1) .kick method wasn't defined in driver
 2) resource_table exists in firmware and has "Virtio device entry" defined

Let's refuse to register an rproc-induced virtio device if no kick method was
defined for rproc.

[   13.180049][  T415] 8<--- cut here ---
[   13.190558][  T415] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   13.212544][  T415] pgd = (ptrval)
[   13.217052][  T415] [00000000] *pgd=00000000
[   13.224692][  T415] Internal error: Oops: 80000005 [#1] PREEMPT SMP ARM
[   13.231318][  T415] Modules linked in: rpmsg_char imx_rproc virtio_rpmsg_bus rpmsg_core [last unloaded: imx_rproc]
[   13.241687][  T415] CPU: 0 PID: 415 Comm: unload-load.sh Not tainted 5.5.2-00002-g70...