RDMA/rtrs: fix uninitialized symbol 'cnt'

rtrs_clt_rdma_cq_direct returns an ninitialized value in cnt
if there is no session. This patch makes rtrs_clt_rdma_cq_direct
returns a negative value for block layer not to try again.

Fixes: 2958a995 ("block/rnbd-clt: Support polling mode for IO latency optimization")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210429092741.266533-1-gi-oh.kim@ionos.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -2896,7 +2896,8 @@ EXPORT_SYMBOL(rtrs_clt_request);
 
 int rtrs_clt_rdma_cq_direct(struct rtrs_clt *clt, unsigned int index)
 {
-	int cnt;
+	/* If no path, return -1 for block layer not to try again */
+	int cnt = -1;
 	struct rtrs_con *con;
 	struct rtrs_clt_sess *sess;
 	struct path_it it;