Makefile.inc: Add fmap_config.h as a dependency to cbfs-struct generation

There is no easy way to add dependencies to cbfs-structs objects and
fmap_config.h is a generated file. Follow-up commits depend on it being
available so add it in the cbfs-struct makefile function.

Change-Id: I7067ff144d38c1ff058825819419b2a2e7801e17
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63350
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/Makefile.inc b/Makefile.inc
index 6b1c45c..654b366 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -337,7 +337,7 @@
 # arg1: C source file
 # arg2: binary file
 cbfs-files-processor-struct= \
-	$(eval $(2): $(1) $(obj)/build.h $(KCONFIG_AUTOHEADER); \
+	$(eval $(2): $(1) $(obj)/build.h $(obj)/fmap_config.h $(KCONFIG_AUTOHEADER); \
 		printf "    CC+STRIP   $(1)\n"; \
 		$(CC_ramstage) -MMD $(CPPFLAGS_ramstage) $(CFLAGS_ramstage) --param asan-globals=0 $$(ramstage-c-ccopts) -include $(KCONFIG_AUTOHEADER) -MT $(2) -o $(2).tmp -c $(1) && \
 		$(OBJCOPY_ramstage) -O binary --set-section-flags .bss*=alloc,contents,load $(2).tmp $(2); \