soc: qcom: cmd-db: Fix an error code in cmd_db_dev_probe()

The memremap() function doesn't return error pointers, it returns NULL.
This code is returning "ret = PTR_ERR(NULL);" which is success, but it
should return -ENOMEM.

Fixes: 312416d9 ("drivers: qcom: add command DB driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

drivers/soc/qcom/cmd-db.c

@@ -248,8 +248,8 @@ static int cmd_db_dev_probe(struct platform_device *pdev)
 	}
 
 	cmd_db_header = memremap(rmem->base, rmem->size, MEMREMAP_WB);
-	if (IS_ERR_OR_NULL(cmd_db_header)) {
-		ret = PTR_ERR(cmd_db_header);
+	if (!cmd_db_header) {
+		ret = -ENOMEM;
 		cmd_db_header = NULL;
 		return ret;
 	}