feat(mt8188): add pinctrl support

Add pinctrl support for MT8188.

TEST=build pass
BUG=b:236331724

Signed-off-by: Jianguo Zhang <jianguo.zhang@mediatek.corp-partner.google.com>
Change-Id: Id4ac8f67009621fff8f15f3ab2d8f200343c8356
diff --git a/plat/mediatek/mt8188/platform.mk b/plat/mediatek/mt8188/platform.mk
index 6f72954..84bcfac 100644
--- a/plat/mediatek/mt8188/platform.mk
+++ b/plat/mediatek/mt8188/platform.mk
@@ -25,6 +25,7 @@
 MODULES-y += $(MTK_PLAT)/drivers/cirq
 MODULES-y += $(MTK_PLAT)/drivers/dp
 MODULES-y += $(MTK_PLAT)/drivers/gic600
+MODULES-y += $(MTK_PLAT)/drivers/gpio
 MODULES-y += $(MTK_PLAT)/drivers/iommu
 MODULES-y += $(MTK_PLAT)/drivers/pmic
 MODULES-y += $(MTK_PLAT)/drivers/pmic_wrap