swap_info: miscellaneous minor cleanups

Move CONFIG_HIBERNATION's swapdev_block() into the main CONFIG_HIBERNATION
block, remove extraneous whitespace and return, fix typo in a comment.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>