ramips: fix mt7688 watchdog register base addr

I found mt7688 watchdog not working. The watchdog registers are identical
for mt7621 and mt7628/mt7688. The first watchdog related register is at
0x10000100, the last one - a 16bit sized - at 0x10000128.

Set the correct register address and size in the dtsi file to get the
watchdog working.

Signed-off-by: lbzhung <gewalalb@gmail.com>
[add commit message]
Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/dts/mt7628an.dtsi

@@ -37,9 +37,9 @@
 			reg = <0x0 0x100>;
 		};
 
-		watchdog: watchdog@120 {
+		watchdog: watchdog@100 {
 			compatible = "ralink,mt7628an-wdt", "mediatek,mt7621-wdt";
-			reg = <0x120 0x10>;
+			reg = <0x100 0x30>;
 
 			resets = <&rstctrl 8>;
 			reset-names = "wdt";