btrfs: unpin_extent_cache: fix the typo and unnecessary arguements

- unpint->unpin
- prealloc is no more used

Signed-off-by: Liu Bo <liub.liubo@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Liu Bo 2012-10-30 17:13:52 +08:00 • committed by Jiri Kosina
commit 52b1de91ea