kbuild: update help in top level Makefile

	@echo  'Cleaning targets:'

	@echo  '  clean		  - remove most generated files but keep the config'

	@echo  '  mrproper	  - remove all generated files + config + various backup files'

	@echo  '  distclean	  - mrproper + patch files'

	@echo  ''

	@echo  'Configuration targets:'

	@$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help

	@echo  '  xconfig	  - Update current config utilising a QT based front-end'

	@echo  '  gconfig	  - Update current config utilising a GTK based front-end'

	@echo  '  oldconfig	  - Update current config utilising a provided .config as base'

	@echo  '  silentoldconfig - Same as oldconfig, but quietly'

	@echo  '  randconfig	  - New config with random answer to all options'

	@echo  '  defconfig	  - New config with default answer to all options'

	@echo  '  allmodconfig	  - New config selecting modules when possible'