dm: gpio: uclass: Add flag to control sequence numbering

Like SPI and I2C few GPIO controllers also have
multiple chip instances. This patch adds the
flag 'DM_UC_FLAG_SEQ_ALIAS' in gpio_uclass driver
to control device sequence numbering. By defalut
the dev->r_seq for gpio_uclass will alwalys
returns -1, which leads the gpio driver probe
failure when using the driver with device trees.
Signed-off-by: NBhuvanchandra DV <bhuvanchandra.dv@toradex.com>

drivers/gpio/gpio-uclass.c

@@ -757,6 +757,7 @@ static int gpio_pre_remove(struct udevice *dev)
 UCLASS_DRIVER(gpio) = {
 	.id		= UCLASS_GPIO,
 	.name		= "gpio",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 	.post_probe	= gpio_post_probe,
 	.pre_remove	= gpio_pre_remove,
 	.per_device_auto_alloc_size = sizeof(struct gpio_dev_priv),