zephyr: stop using CONFIG_SOF to identify Zephyr build

Prepare for change in Zephyr to drop SOF module from the upstream
Zephyr manifest. Remove use of CONFIG_SOF which is defined in
work/zephyr/modules/Kconfig.sof, but will now be removed.

Fix this by using CONFIG_ZEPHYR_SOF_MODULE instead. This is defined
by the Zephyr build system when using the work/sof/west.yml for
building SOF. If SOF is built without Zephyr (e.g. testbench or cmocka
build), this define will not be set.

After this change, one must use the SOF work/sof/west.yml manifest
to build SOF with Zephyr. This is used by all public instructions
and CI jobs already.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

app/prj.conf

@@ -1,4 +1,3 @@
-CONFIG_SOF=y
 CONFIG_BUILD_OUTPUT_BIN=n
 
 # The additional stripped .elf files are deterministic.

zephyr/CMakeLists.txt

@@ -2,7 +2,7 @@
 # compile every Zephyr module that can be found. See
 # sof/zephyr/module.yml and
 # https://docs.zephyrproject.org/latest/develop/modules.html
-if(CONFIG_SOF)
+if(CONFIG_ZEPHYR_SOF_MODULE)
 
 if(CONFIG_ZEPHYR_POSIX)
 	set(ARCH host)
@@ -555,4 +555,4 @@ include(../scripts/cmake/uuid-registry.cmake)
 # Create Trace realtive file paths
 sof_append_relative_path_definitions(modules_sof)
 
-endif() # CONFIG_SOF
+endif() # CONFIG_ZEPHYR_SOF_MODULE

zephyr/Kconfig

@@ -1,5 +1,3 @@
-if SOF
-
 config SOF_STAGING
 	bool "Enable SOF staging features and modules"
 	help
@@ -166,5 +164,3 @@ config STACK_SIZE_IPC_TX
 	default 2048
 	help
 	  IPC sender work-queue thread stack size. Keep a power of 2.
-
-endif