block: remove __blk_put_request()

Now there's no difference between blk_put_request() and
__blk_put_request() anymore, get rid of the underscore version and
convert the few callers.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/scsi/osst.c

@@ -341,7 +341,7 @@ static void osst_end_async(struct request *req, blk_status_t status)
 		blk_rq_unmap_user(SRpnt->bio);
 	}
 
-	__blk_put_request(req->q, req);
+	blk_put_request(req);
 }
 
 /* osst_request memory management */