MAINTAINERS: remove section SMX UIO Interface

Commit d6e976c0 ("UIO: Remove SMX
Cryptengine driver") removed the file.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Ben Nizette <bn@niasdigital.com>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>