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>