NTB: ntb_tool: Add check for devm_kcalloc

As the devm_kcalloc may return NULL pointer,
it should be better to add check for the return
value, as same as the others.

Fixes: 7f46c8b ("NTB: ntb_tool: Add full multi-port NTB API support")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

Author: JiangJias

drivers/ntb/test/ntb_tool.c

@@ -998,6 +998,8 @@ static int tool_init_mws(struct tool_ctx *tc)
 		tc->peers[pidx].outmws =
 			devm_kcalloc(&tc->ntb->dev, tc->peers[pidx].outmw_cnt,
 				   sizeof(*tc->peers[pidx].outmws), GFP_KERNEL);
+		if (tc->peers[pidx].outmws == NULL)
+			return -ENOMEM;
 
 		for (widx = 0; widx < tc->peers[pidx].outmw_cnt; widx++) {
 			tc->peers[pidx].outmws[widx].pidx = pidx;