Pull devicetree updates from Rob Herring:

 - Update dtc to upstream version v1.6.0-31-gcbca977ea121

 - dtx_diff help text reformatting

 - Speed-up validation time for binding and dtb checks using json for
   intermediate files

 - Add support for running yamllint on DT schema files

 - Remove old booting-without-of.rst

 - Extend the example schema to address common issues

 - Cleanup handling of additionalProperties/unevaluatedProperties

 - Ensure all DSI controller schemas reference dsi-controller.yaml

 - Vendor prefixes for Zealz, Wandbord/Technexion, Embest RIoT, Rex,
   DFI, and Cisco Meraki

 - Convert at25, SPMI bus, TI hwlock, HiSilicon Hi3660 USB3 PHY, Arm
   SP805 watchdog, Arm SP804, and Samsung 11-pin USB connector to DT
   schema

 - Convert HiSilicon SoC and syscon bindings to DT schema

 - Convert SiFive Risc-V L2 cache, PLIC, PRCI, and PWM to DT schema

 - Convert i.MX bindings for w1, crypto, ...