zephyr: Allow a custom dts.

Allows using custom DTS things such as bindings.

Signed-off-by: Vdragon <mail@massdriver.space>

ports/zephyr/CMakeLists.txt

@@ -35,6 +35,8 @@ string(TOUPPER          ZEPHYR_${BOARD} MICROPY_BOARD)
 include(${MICROPY_DIR}/py/py.cmake)
 include(${MICROPY_DIR}/extmod/extmod.cmake)
 
+list(APPEND DTS_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/dts)
+
 if (CONFIG_MICROPY_FROZEN_MODULES)
     cmake_path(ABSOLUTE_PATH CONFIG_MICROPY_FROZEN_MANIFEST BASE_DIRECTORY ${CMAKE_CURRENT_LIST_DIR})
     set(MICROPY_FROZEN_MANIFEST ${CONFIG_MICROPY_FROZEN_MANIFEST})

ports/zephyr/dts/bindings/vendor-prefixes.txt

@@ -0,0 +1,15 @@
+# Device tree binding vendor prefix registry. Keep this list in
+# alphabetical order.
+#
+# This isn't an exhaustive list, but you should add new prefixes to it
+# before using them to avoid name-space collisions.
+#
+# The contents of this file are parsed during documentation generation.
+# Anything that starts with a '#' is treated as a comment and ignored.
+# Non-empty lines should be in this format:
+#
+# <vendor-prefix><TAB><Full name of vendor>
+
+# zephyr-keep-sorted-start
+micropython	MicroPython Project
+# zephyr-keep-sorted-stop