kbuild: Move archhelp to arch/$(ARCH)/Makefile

arch/$(ARCH)/Makefile already contains the kbuild required additions
to allow the kernel to be built for the architecture in question.
Moving archhelp centralise this information, and no longer require a
boot directory to exist to utilise this feature.
  
Update i386 to define archhelp in arch/$(ARCH)/Makefile
Other architectures will be updated in next cset.

Makefile

@@ -810,7 +810,8 @@ help:
 	@$(MAKE) --no-print-directory -f Documentation/DocBook/Makefile dochelp
 	@echo  ''
 	@echo  'Architecture specific targets ($(ARCH)):'
-	@$(MAKE) --no-print-directory -f arch/$(ARCH)/boot/Makefile archhelp
+	@$(if $(archhelp),$(archhelp),\
+		echo '  No architecture specific help defined for $(ARCH)')
 	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info browse Documentation/kbuild/*'

arch/i386/Makefile

@@ -109,3 +109,12 @@ install: vmlinux
 
 archclean:
 	$(Q)$(MAKE) $(clean)=arch/i386/boot
+
+define archhelp
+  echo  '* bzImage	- Compressed kernel image (arch/$(ARCH)/boot/bzImage)'
+  echo  '  install	- Install kernel using'
+  echo  '		   (your) ~/bin/installkernel or'
+  echo  '		   (distribution) /sbin/installkernel or'
+  echo  '		   install to $$(INSTALL_PATH) and run lilo'
+endef
+

arch/i386/boot/Makefile

@@ -74,11 +74,3 @@ zlilo: $(BOOTIMAGE)
 
 install: $(BOOTIMAGE)
 	sh $(src)/install.sh $(KERNELRELEASE) $(BOOTIMAGE) System.map "$(INSTALL_PATH)"
-
-archhelp:
-	@echo  '* bzImage	- Compressed kernel image (arch/$(ARCH)/boot/bzImage)'
-	@echo  '  install	- Install kernel using'
-	@echo  '                  (your) ~/bin/installkernel or'
-	@echo  '                  (distribution) /sbin/installkernel or'
-	@echo  '        	  install to $$(INSTALL_PATH) and run lilo'
-