Fix up MAINTAINERS file problems

Fix up MAINTAINERS file problems

Prepping for scripting the MAINTAINERS file cleanup (and possible split)
showed a couple of cases where the headers for a couple of entries were
bogus.

There's a few different kinds of bogosities:

 - the X-GENE SOC EDAC case was confused and split over two lines

 - there were four entries for "GREYBUS PROTOCOLS DRIVERS" that were all
   different things.

 - the NOKIA N900 CAMERA SUPPORT" was duplicated

all of which were more obvious when you started doing associative arrays
in perl to track these things by the header (so that we can alphabetize
this thing properly, and so that we might split it up by the data too).

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