get_mergeable_page() can only return NULL (also in case of errors) or the
pinned mergeable page. It can't return an error different than NULL.
This optimizes away the unnecessary error check.
Add a return after the "out:" label in the callee to make it more
readable.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Petr Holasek <pholasek@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>