dm: gpio: Return error when pull up/down is requested but set_flags ops is not implmentated

Currently in _dm_gpio_set_flags() when set_flags ops is not implemented
direction_output()/_input() is used, but pull up/down is not supported by
these ops.

Signed-off-by: Zixun LI <admin@hifiphile.com>
diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c
index 0213271..da929c3 100644
--- a/drivers/gpio/gpio-uclass.c
+++ b/drivers/gpio/gpio-uclass.c
@@ -705,6 +705,9 @@
 	if (ops->set_flags) {
 		ret = ops->set_flags(dev, desc->offset, flags);
 	} else {
+		if (flags & GPIOD_MASK_PULL)
+			return -EINVAL;
+
 		if (flags & GPIOD_IS_OUT) {
 			bool value = flags & GPIOD_IS_OUT_ACTIVE;