x86: Fix the $(ARCH) dependent help output in the top Makefile

Change the $(ARCH) dependency to $(SRCARCH) to honor the x86
namespace for i386 and x86_64.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Makefile

@@ -1141,7 +1141,7 @@ help:
 	@echo  '  cscope	  - Generate cscope index'
 	@echo  '  kernelrelease	  - Output the release version string'
 	@echo  '  kernelversion	  - Output the version stored in Makefile'
-	@if [ -r $(srctree)/include/asm-$(ARCH)/Kbuild ]; then \
+	@if [ -r $(srctree)/include/asm-$(SRCARCH)/Kbuild ]; then \
 	 echo  '  headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
 	 echo  '                    (default: $(INSTALL_HDR_PATH))'; \
 	 fi
@@ -1149,7 +1149,7 @@ help:
 	@echo  'Static analysers'
 	@echo  '  checkstack      - Generate a list of stack hogs'
 	@echo  '  namespacecheck  - Name space analysis on compiled kernel'
-	@if [ -r $(srctree)/include/asm-$(ARCH)/Kbuild ]; then \
+	@if [ -r $(srctree)/include/asm-$(SRCARCH)/Kbuild ]; then \
 	 echo  '  headers_check   - Sanity check on exported headers'; \
 	 fi
 	@echo  ''