pinctrl: mediatek: add driver for MT8512

Add Pinctrl driver for MediaTek MT8512 SoC.

diff --git a/drivers/pinctrl/mediatek/Kconfig b/drivers/pinctrl/mediatek/Kconfig
index 22ee623..9c6b580 100644
--- a/drivers/pinctrl/mediatek/Kconfig
+++ b/drivers/pinctrl/mediatek/Kconfig
@@ -12,6 +12,10 @@
 	bool "MT7629 SoC pinctrl driver"
 	select PINCTRL_MTK
 
+config PINCTRL_MT8512
+	bool "MT8512 SoC pinctrl driver"
+	select PINCTRL_MTK
+
 config PINCTRL_MT8516
 	bool "MT8516 SoC pinctrl driver"
 	select PINCTRL_MTK