[SCSI] destroy scsi_bidi_sdb_cache in scsi_exit_queue

Needs to call kmem_cache_destroy for scsi_bidi_sdb_cache in
scsi_exit_queue.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/scsi_lib.c

@@ -1712,6 +1712,7 @@ void scsi_exit_queue(void)
 	int i;
 
 	kmem_cache_destroy(scsi_io_context_cache);
+	kmem_cache_destroy(scsi_bidi_sdb_cache);
 
 	for (i = 0; i < SG_MEMPOOL_NR; i++) {
 		struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;