[PATCH] fat: remove the unneeded vfat_find() in vfat_rename()

Now, vfat_rename() is using vfat_find() for sanity check.  This removes that
sanity check, the cost of sanity check is too high.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>