arm64: dts: mediatek: mt8186: Fix watchdog compatible

MT8186's watchdog embeds a reset controller and needs only the
mediatek,mt8186-wdt compatible string as the MT6589 one is there
for watchdogs that don't have any reset controller capability.

Fixes: 2e78620b ("arm64: dts: Add MediaTek MT8186 dts and evaluation board and Makefile")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Co-developed-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20221108033209.22751-2-allen-kh.cheng@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>