This adds minimal support for the MediaTek 8365 SOC and the EVK reference
board, allowing the board to boot to initramfs with serial port I/O.

v3:
  - Remove a number of components that are not yet supported (they will
    come back alongside the corresponding drivers)
  - Address issues found by dt_binding_check (mostly fixing pinctrl
    bindings)
  - Address issues pointed out in comments
  - Reorder patches

v2:
  - Add missing dt-bindings documentation
  - Small cleanups addressing issues in v1 pointed out by Krzysztof Kozlowski