core: lib: scmi-server: add CMake defines for embedded modules

Enable CMake directive CMAKE_C_COMPILER_WORKS to prevent SCP-firmware
CMake configuration sequence to check the cross compilation toolchain
since it is not needed here: OP-TEE only uses CMake to configure
SCP-firmware, not to build source files. This change is required when
building OP-TEE with CFG_SCMI_SCPFW=y and using a CMake >= 3.27.0.

Suggested-by: Thomas Bourgoin <thomas.bourgoin@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
[Fix the overwrite of others CMake options]
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

core/lib/scmi-server/sub.mk

@@ -28,6 +28,11 @@ scpfw-cmake-flags-y = -DSCP_FIRMWARE_SOURCE_DIR:PATH=$(scpfw-product)/fw \
 		      -DSCP_OPTEE_DIR:PATH=$(CURDIR) \
 		      -DCFG_CROSS_COMPILE=$(lastword $(CROSS_COMPILE_core))
 
+# CMake does not need to check the cross compilation toolchain since we do not
+# compile any source file with CMake, we only generate some SCP-firmware
+# files.
+scpfw-cmake-flags-y += -DCMAKE_C_COMPILER_WORKS=1
+
 ifeq ($(cmd-echo-silent),true)
 scpfw-cmake-redirect = >/dev/null
 endif