IB/core: remove redundant check on prot_sg_cnt

prot_sg_cnt cannot be zero as a previous check on ret (from which
prot_sg_cnt is assigned) returns -ENOMEM if is it zero.  Since
it cannot be zero we can simplify the code by removing the non
-zero check on prot_sg_cnt and redundant else statement.

Detected by CoverityScan, COD#1357188 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/rw.c

@@ -384,7 +384,6 @@ int rdma_rw_ctx_signature_init(struct rdma_rw_ctx *ctx, struct ib_qp *qp,
 	count += ret;
 	prev_wr = &ctx->sig->data.reg_wr.wr;
 
-	if (prot_sg_cnt) {
 	ret = rdma_rw_init_one_mr(qp, port_num, &ctx->sig->prot,
 				  prot_sg, prot_sg_cnt, 0);
 	if (ret < 0)
@@ -396,9 +395,6 @@ int rdma_rw_ctx_signature_init(struct rdma_rw_ctx *ctx, struct ib_qp *qp,
 	else
 		prev_wr->next = &ctx->sig->prot.reg_wr.wr;
 	prev_wr = &ctx->sig->prot.reg_wr.wr;
-	} else {
-		ctx->sig->prot.mr = NULL;
-	}
 
 	ctx->sig->sig_mr = ib_mr_pool_get(qp, &qp->sig_mrs);
 	if (!ctx->sig->sig_mr) {