MAINTAINERS: remove section STRIP

Commit f80a3f62 ("Staging: strip: delete
the driver") removed it.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>