Cleanup: use #elif instead of #end and #elif.

Link: https://lkml.kernel.org/r/20201015150736.GA91603@rlkSigned-off-by: Hui Su <sh_def@163.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>