Separate the setting of device I/O limits from dm_get_device().  dm-loop will
use this.
Signed-off-by: NBryn Reeves <breeves@redhat.com>
Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>