kbuild: create symbolic link only for ARM, AVR32, SPARC, PowerPC, x86

The symbolic link to SoC/CPU specific header directory is created
during the build, while it is only necessary for ARM, AVR32, SPARC,
x86, and some CPUs of PowerPC.  For the other architectures, it just
results in a broken symbolic link.

Introduce CONFIG_CREATE_ARCH_SYMLINK to not create unneeded symbolic
links.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/Kconfig

+config CREATE_ARCH_SYMLINK
+	bool
+
 config HAVE_GENERIC_BOARD
 	bool
 
@@ -18,12 +21,14 @@ config ARC
 
 config ARM
 	bool "ARM architecture"
+	select CREATE_ARCH_SYMLINK
 	select HAVE_PRIVATE_LIBGCC if !ARM64
 	select HAVE_GENERIC_BOARD
 	select SUPPORT_OF_CONTROL
 
 config AVR32
 	bool "AVR32 architecture"
+	select CREATE_ARCH_SYMLINK
 	select HAVE_GENERIC_BOARD
 	select SYS_GENERIC_BOARD
 
@@ -84,9 +89,11 @@ config SH
 
 config SPARC
 	bool "SPARC architecture"
+	select CREATE_ARCH_SYMLINK
 
 config X86
 	bool "x86 architecture"
+	select CREATE_ARCH_SYMLINK
 	select HAVE_PRIVATE_LIBGCC
 	select HAVE_GENERIC_BOARD
 	select SYS_GENERIC_BOARD

arch/powerpc/Kconfig

@@ -22,9 +22,11 @@ config MPC8260
 
 config MPC83xx
 	bool "MPC83xx"
+	select CREATE_ARCH_SYMLINK
 
 config MPC85xx
 	bool "MPC85xx"
+	select CREATE_ARCH_SYMLINK
 
 config MPC86xx
 	bool "MPC86xx"
@@ -34,6 +36,7 @@ config 8xx
 
 config 4xx
 	bool "PPC4xx"
+	select CREATE_ARCH_SYMLINK
 
 endchoice
 

scripts/Makefile.autoconf

@@ -107,6 +107,7 @@ include/config.h: scripts/Makefile.autoconf create_symlink FORCE
 # Otherwise, create a symbolic link to arch/$(ARCH)/include/asm/arch-$(SOC).
 PHONY += create_symlink
 create_symlink:
+ifdef CONFIG_CREATE_ARCH_SYMLINK
 ifneq ($(KBUILD_SRC),)
 	$(Q)mkdir -p include/asm
 	$(Q)if [ -d $(KBUILD_SRC)/arch/$(ARCH)/mach-$(SOC)/include/mach ]; then	\
@@ -123,6 +124,7 @@ else
 	fi;								\
 	ln -fsn $$dest arch/$(ARCH)/include/asm/arch
 endif
+endif
 
 PHONY += FORCE
 FORCE: