dt-bindings: i2c: i2c-mt65xx: Add compatible for MT8189 SoC

dt-bindings: i2c: i2c-mt65xx: Add compatible for MT8189 SoC

Add compatible string for MT8189 SoC.
Its multiple I2C controller instances are compatible with the ones
found in the MT8188 SoC.

Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>