Remove 'M' variants of lock macros

Remove 'M' variants of lock macros

Since the beginning, we've had M variants of the lock macros, which
are identical to the normal form. Dispose of these variants, to make
it clearer what's going on.

Change-Id: I0b7708ec670ef0edb4c1dc21d472e5041d31f6a2
Reviewed-on: http://gerrit.openafs.org/807
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>