Makefile: Update kselftest help information

	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'

	@echo  ''

	@echo  'Kernel selftest:'

	@echo  '  kselftest       - Build and run kernel selftest (run as root)'

	@echo  '  kselftest         - Build and run kernel selftest'

	@echo  '                      Build, install, and boot kernel before'

	@echo  '                      running kselftest on it'

	@echo  '                      Run as root for full coverage'

	@echo  '  kselftest-all     - Build kernel selftest'

	@echo  '  kselftest-install - Build and install kernel selftest'

	@echo  '  kselftest-clean   - Remove all generated kselftest files'

	@echo  '  kselftest-merge - Merge all the config dependencies of kselftest to existing'

	@echo  '                    .config.'

	@echo  '  kselftest-merge   - Merge all the config dependencies of'

	@echo  '		      kselftest to existing .config.'

	@echo  ''

	@$(if $(dtstree), \

		echo 'Devicetree:'; \