CMakelists: Support HWMv2 structure

Change the criteria so that not only `variants/${BOARD}` but also
`variants/${BOARD}${BOARD_QUALIFIERS}` are valid as variant paths.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

CMakeLists.txt

@@ -1,8 +1,16 @@
 # SPDX-License-Identifier: Apache-2.0
 
+if (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/variants/${BOARD})
+  set(variant_dir variants/${BOARD})
+elseif (IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS})
+  set(variant_dir variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS})
+else()
+  message(FATAL_ERROR "Variant dir not found: variants/${BOARD}, variants/${BOARD}${NORMALIZED_BOARD_QUALIFIERS}")
+endif()
+
 if (CONFIG_ARDUINO_API)
 add_subdirectory(cores)
 add_subdirectory(libraries)
-zephyr_include_directories(variants/${BOARD})
+zephyr_include_directories(${variant_dir})
 endif()