Makefile: Add cleanall-TARGET and cleansstate-TARGET
Makefile: Add cleanall-TARGET and cleansstate-TARGET

These add granularity to the cleaning choices.  While here re-organize
the help output of clean* slightly.

Signed-off-by: Tom Rini <4c3d5c8f8c21c27dd329bd585f481113514551fd@mentor.com>

kergoth/oe-core-template