edac: add MAINTAINERS entry for i5400 EDAC driver

i5400 EDAC driver were added upstream by those changesets:

 - 920c8df6 "edac: driver for i5400 MCH (Seaburg)"
 - 8375d490 "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>

MAINTAINERS

@@ -1581,6 +1581,13 @@ L:	bluesmoke-devel@lists.sourceforge.net
 W:	bluesmoke.sourceforge.net
 S:	Maintained
 
+EDAC-I5400
+P:	Mauro Carvalho Chehab
+M:	mchehab@redhat.com
+L:	bluesmoke-devel@lists.sourceforge.net
+W:	bluesmoke.sourceforge.net
+S:	Maintained
+
 EDAC-I82975X
 P:	Ranganathan Desikan
 P:	Arvind R.