gpio: dw: Add a trailing underscore to generated name

Previously, if there was no bank-name property, it was easy to have
confusing gpio names like "gpio1@08", instead of "gpio1@0_8". This patch
follows the example of the sifive gpio driver.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
index bf324f5..a52c9e1 100644
--- a/drivers/gpio/dwapb_gpio.c
+++ b/drivers/gpio/dwapb_gpio.c
@@ -186,7 +186,15 @@
 			 * Fall back to node name. This means accessing pins
 			 * via bank name won't work.
 			 */
-			plat->name = ofnode_get_name(node);
+			char name[32];
+
+			snprintf(name, sizeof(name), "%s_",
+				 ofnode_get_name(node));
+			plat->name = strdup(name);
+			if (!plat->name) {
+				kfree(plat);
+				return -ENOMEM;
+			}
 		}
 
 		ret = device_bind_ofnode(dev, dev->driver, plat->name,