sunxi: gpio: Rename GPIOs to include a 'P' prefix

By convention, sunxi GPIOs are named PA1, PA2 instead of A1, A2. Change
the driver model GPIO driver for sunxi to use these names.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/gpio/sunxi_gpio.c

@@ -249,10 +249,11 @@ static char *gpio_bank_name(int bank)
 {
 	char *name;
 
-	name = malloc(2);
+	name = malloc(3);
 	if (name) {
-		name[0] = 'A' + bank;
-		name[1] = '\0';
+		name[0] = 'P';
+		name[1] = 'A' + bank;
+		name[2] = '\0';
 	}
 
 	return name;