ramips: ZTE-Q7: fix switch driver initialization in DTS (FS#716)

Add the changes suggested by FS#716 to fix the switch driver initialization
on the ZTE Q7.

Also remove the `pinctrl-names` field obsoleted by the changes.

Reported-by: Harry Lau <harrylwc@gmail.com>
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/ramips/dts/ZTE-Q7.dts

@@ -89,8 +89,6 @@
 };
 
 &ethernet {
-	pinctrl-names = "default";
-	pinctrl-0 = <&ephy_pins>;
 	mtd-mac-address = <&factory 0x4>;
 	mediatek,portmap = "wllll";
 };
@@ -110,3 +108,7 @@
 &ohci {
 	status = "okay";
 };
+
+&gsw {
+	mediatek,port4 = "ephy";
+};