ath79: add missing reset-gpios for NanoStation Loco M (XW)

When porting support from ar71xx to ath79, the reset-gpios option was
missed. Due to a hardware bug, this would eventually leave the devices
with RX-deaf Ethernet PHY.
Signed-off-by: Roger Pueyo Centelles <roger.pueyo@guifi.net>
(cherry picked from commit 6613a7f5)

target/linux/ath79/dts/ar9342_ubnt_nanostation-loco-m-xw.dts

@@ -19,6 +19,7 @@
 	phy1: ethernet-phy@1 {
 		reg = <1>;
 		phy-mode = "mii";
+		reset-gpios = <&gpio 0 GPIO_ACTIVE_LOW>;
 	};
 };