kbuild: Let 'make help' point to README

Documentation/kbuild are now limited to kernel development information,
so there is no point asking people to look there, when
searching information about building the kernel.
Pinting to README makes most sense

Makefile

@@ -5,7 +5,7 @@ EXTRAVERSION =
 
 # *DOCUMENTATION*
 # To see a list of typical targets execute "make help"
-# More info can be located in ./Documentation/kbuild
+# More info can be located in ./README
 # Comments in this file are targeted only to the developer, do not
 # expect to learn how to build the kernel reading this file.
 
@@ -828,7 +828,7 @@ help:
 	@echo  '  make C=1   [targets] Check all c source with checker tool'
 	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
-	@echo  'For further info browse Documentation/kbuild/*'
+	@echo  'For further info see the ./README file'
 
 
 # Documentation targets