xfs: remove the XBF_STALE check from xfs_buf_rele_cached

xfs_buf_stale already set b_lru_ref to 0, and thus prevents the buffer
from moving to the LRU.  Remove the duplicate check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>