MAINTAINERS: update MCA section

The MCA section included a file referring to Machine Check rather than
Microchannel.

Rename the section to spell out Microchannel and drop the bad file
reference.
Reported-by: NGreg Pearson <greg.pearson@hp.com>
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -4416,6 +4416,13 @@ T:	git git://git.monstr.eu/linux-2.6-microblaze.git
 S:	Supported
 F:	arch/microblaze/
 
+MICROCHANNEL ARCHITECTURE (MCA)
+M:	James Bottomley <James.Bottomley@HansenPartnership.com>
+S:	Maintained
+F:	Documentation/mca.txt
+F:	drivers/mca/
+F:	include/linux/mca*
+
 MICROTEK X6 SCANNER
 M:	Oliver Neukum <oliver@neukum.name>
 S:	Maintained
@@ -4431,14 +4438,6 @@ S:	Supported
 F:	Documentation/mips/
 F:	arch/mips/
 
-MISCELLANEOUS MCA-SUPPORT
-M:	James Bottomley <James.Bottomley@HansenPartnership.com>
-S:	Maintained
-F:	Documentation/ia64/mca.txt
-F:	Documentation/mca.txt
-F:	drivers/mca/
-F:	include/linux/mca*
-
 MODULE SUPPORT
 M:	Rusty Russell <rusty@rustcorp.com.au>
 S:	Maintained