tty: st-asc: switch to using devm_gpiod_get()

The node pointer in question is not a child node, but the node assigned
to the port device itself, so we should not be using
devm_fwnode_get_gpiod_from_child() [that is going away], but standard
devm_gpiod_get().

To maintain the previous labeling we use gpiod_set_consumer_name() after
we acquire the GPIO.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20200104202314.GA13591@dtor-wsSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/st-asc.c

@@ -504,7 +504,6 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 			    struct ktermios *old)
 {
 	struct asc_port *ascport = to_asc_port(port);
-	struct device_node *np = port->dev->of_node;
 	struct gpio_desc *gpiod;
 	unsigned int baud;
 	u32 ctrl_val;
@@ -566,13 +565,12 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 			pinctrl_select_state(ascport->pinctrl,
 					     ascport->states[NO_HW_FLOWCTRL]);
 
-			gpiod = devm_fwnode_get_gpiod_from_child(port->dev,
-								 "rts",
-								 &np->fwnode,
-								 GPIOD_OUT_LOW,
-								 np->name);
-			if (!IS_ERR(gpiod))
+			gpiod = devm_gpiod_get(port->dev, "rts", GPIOD_OUT_LOW);
+			if (!IS_ERR(gpiod)) {
+				gpiod_set_consumer_name(gpiod,
+						port->dev->of_node->name);
 				ascport->rts = gpiod;
+			}
 		}
 	}