include/linux/bitmap.h: turn bitmap_set and bitmap_clear into memset when possible

include/linux/bitmap.h: turn bitmap_set and bitmap_clear into memset when possible

Several callers have constant 'start' and an 'nbits' that is a multiple
of 8, so we can turn them into calls to memset.  We don't need the
entirety of 'start' and 'nbits' to be constant, we just need to know
whether they're divisible by 8.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox <[email protected]>
Acked-by: Rasmus Villemoes <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>