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

@@ -384,21 +384,17 @@ 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)
-			goto out_destroy_data_mr;
-		count += ret;
+	ret = rdma_rw_init_one_mr(qp, port_num, &ctx->sig->prot,
+				  prot_sg, prot_sg_cnt, 0);
+	if (ret < 0)
+		goto out_destroy_data_mr;
+	count += ret;
 
-		if (ctx->sig->prot.inv_wr.next)
-			prev_wr->next = &ctx->sig->prot.inv_wr;
-		else
-			prev_wr->next = &ctx->sig->prot.reg_wr.wr;
-		prev_wr = &ctx->sig->prot.reg_wr.wr;
-	} else {
-		ctx->sig->prot.mr = NULL;
-	}
+	if (ctx->sig->prot.inv_wr.next)
+		prev_wr->next = &ctx->sig->prot.inv_wr;
+	else
+		prev_wr->next = &ctx->sig->prot.reg_wr.wr;
+	prev_wr = &ctx->sig->prot.reg_wr.wr;
 
 	ctx->sig->sig_mr = ib_mr_pool_get(qp, &qp->sig_mrs);
 	if (!ctx->sig->sig_mr) {