soc: mediatek: mediatek-regulator-coupler: Support mt8188

The Mali GPU in mt8188 also requires coupled power supplies,
that is, the "vsram" voltage should follow the "vgpu" voltage.
Therefore add the compatible to enable this coupling behavior.

Signed-off-by: Pablo Sun <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: AngeloGioacchino Del Regno <[e-mail]>

drivers/soc/mediatek/mtk-regulator-coupler.c

···
 {
 	if (!of_machine_is_compatible("mediatek,mt8183") &&
 	    !of_machine_is_compatible("mediatek,mt8186") &&
+	    !of_machine_is_compatible("mediatek,mt8188") &&
 	    !of_machine_is_compatible("mediatek,mt8192"))
 		return 0;