edac: add MAINTAINERS entry for i5400 EDAC driver

edac: add MAINTAINERS entry for i5400 EDAC driver

i5400 EDAC driver were added upstream by those changesets:

 - 69493b20dc29f1a8f8fca0104dbe792003c03381 "edac: driver for i5400 MCH (Seaburg)"
 - b1abf233edde0ce5779252f6098f557e417643de "edac: driver for i5400 MCH (update)"

Update MAINTAINERS entry for this file to correspond to the driver
maintainer.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Ben Woodard <woodard@redhat.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>