Makefile: Update kselftest help information

Update kselftest help information.
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Makefile

@@ -1486,12 +1486,15 @@ help:
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
 	@echo  ''
 	@echo  'Kernel selftest:'
-	@echo  '  kselftest       - Build and run kernel selftest (run as root)'
-	@echo  '                    Build, install, and boot kernel before'
-	@echo  '                    running kselftest on it'
-	@echo  '  kselftest-clean - Remove all generated kselftest files'
-	@echo  '  kselftest-merge - Merge all the config dependencies of kselftest to existing'
-	@echo  '                    .config.'
+	@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'
+	@echo  '		      kselftest to existing .config.'
 	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \