dt-binding: mediatek: watchdog: fix the description of compatible

The watchdog driver for MT2712 and MT8183 relies on DT data, so
the fallback compatible MT6589 won't work.
Signed-off-by: Crystal Guo <crystal.guo@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201014131936.20584-2-crystal.guo@mediatek.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Documentation/devicetree/bindings/watchdog/mtk-wdt.txt

@@ -4,13 +4,13 @@ Required properties:
 
 - compatible should contain:
 	"mediatek,mt2701-wdt", "mediatek,mt6589-wdt": for MT2701
-	"mediatek,mt2712-wdt", "mediatek,mt6589-wdt": for MT2712
+	"mediatek,mt2712-wdt": for MT2712
 	"mediatek,mt6589-wdt": for MT6589
 	"mediatek,mt6797-wdt", "mediatek,mt6589-wdt": for MT6797
 	"mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
 	"mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
 	"mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
-	"mediatek,mt8183-wdt", "mediatek,mt6589-wdt": for MT8183
+	"mediatek,mt8183-wdt": for MT8183
 	"mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
 
 - reg : Specifies base physical address and size of the registers.