Make memblock_is_memory() and memblock_is_reserved return bool to
improve readability due to these particular functions only using either
one or zero as their return value.

No functional change.
Signed-off-by: NYaowei Bai <baiyaowei@cmss.chinamobile.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>