The watchdog timer of mt8186. mt8195 and mt7986 have their DT data.
We should not use 'mediatek,mt6589-wdt' as fallback.
For mediatek,wdt example of mt8183, We remove mediatek,mt6589-wdt fallback.
Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for MediaTek MT8186")
Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for Mediatek MT8195")
Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for Mediatek MT7986")
Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add #reset-cells")
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@xxxxxxxxxxxx>