ramips: Fix a few other GnuBee DTS differences

I was carrying a local commit that added the sdhci stuff and missed it
as a result.

Also fix the rgmii3 thing in the PC2 DTS file as that's bogus and causes
a dmesg warning that it's bogus.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

target/linux/ramips/dts/GB-PC1.dts

@@ -58,6 +58,9 @@
 
 &sdhci {
 	status = "okay";
+
+	pinctrl-names = "default";
+	pinctrl-0 = <&sdhci_pins>;
 };
 
 &spi0 {

target/linux/ramips/dts/GB-PC2.dts

@@ -126,7 +126,7 @@
 &pinctrl {
 	state_default: pinctrl0 {
 		gpio {
-			ralink,group = "jtag", "rgmii3", "uart3", "wdt";
+			ralink,group = "jtag", "rgmii2", "uart3", "wdt";
 			ralink,function = "gpio";
 		};
 	};