Implementing support for CONFIG_BUILD_ONLY_NO_BLOBS for stm32wbax hci and 802154 drivers

[asm5878]

Summary

CONFIG_BUILD_ONLY_NO_BLOBS should be implemented for stm32wbax hci driver to enable CI build tests.

Describe the solution you'd like

Enabling this configuration we can be sure reference bluetooth samples ("peripheral" and "central") can be built during CI tests.

See:

zephyr/samples/bluetooth/central/sample.yaml

Line 12 in bfea9cf

sample.bluetooth.central.no_blobs:

zephyr/samples/bluetooth/peripheral/sample.yaml

Line 22 in bfea9cf

sample.bluetooth.peripheral.no_blobs:

https://github.com/zephyrproject-rtos/zephyr/blob/main/modules/hal_silabs/simplicity_sdk/src/blob_stubs.c

Alternatives

No response

Additional Context

No response

[jhedberg]

A couple more relevant references for how the Silabs HCI driver does this (you might also want to take a look at ESP32, since they might be doing this slightly differently):
Kconfig dependencies:

zephyr/drivers/bluetooth/hci/Kconfig

Line 158 in 0a339a2

depends on ZEPHYR_HAL_SILABS_MODULE_BLOBS || BUILD_ONLY_NO_BLOBS

Wrapper for linking with blobs:

zephyr/modules/hal_silabs/simplicity_sdk/CMakeLists.txt

Lines 38 to 46 in 0a339a2

	function(add_prebuilt_library lib_name prebuilt_path)
	if(NOT CONFIG_BUILD_ONLY_NO_BLOBS)
	add_library(${lib_name} STATIC IMPORTED GLOBAL)
	set_target_properties(${lib_name} PROPERTIES
	IMPORTED_LOCATION ${BLOBS_DIR}/${prebuilt_path}
	)
	zephyr_link_libraries(${lib_name})
	endif()
	endfunction()

Include the stubs c-file in the build when necessary:

zephyr/modules/hal_silabs/simplicity_sdk/CMakeLists.txt

Lines 333 to 336 in 0a339a2

	zephyr_library_sources_ifdef(
	CONFIG_BUILD_ONLY_NO_BLOBS
	src/blob_stubs.c
	)

[asm5878]

Now we have the 802154 blobs for stm32wbax socs so we need to extend this feature.