pinctrl: mtmips: add support for MediaTek MT7620 SoC

This patch adds pinctrl support for MediaTek MT7620 SoC.
The MT7620 SoC supports only pinmux.

Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/pinctrl/mtmips/Kconfig b/drivers/pinctrl/mtmips/Kconfig
index 8482a38..844d5b7 100644
--- a/drivers/pinctrl/mtmips/Kconfig
+++ b/drivers/pinctrl/mtmips/Kconfig
@@ -3,6 +3,15 @@
 	depends on ARCH_MTMIPS
 	bool
 
+config PINCTRL_MT7620
+	bool "MediaTek MT7620 pin control driver"
+	select PINCTRL_MTMIPS
+	depends on SOC_MT7620 && PINCTRL_GENERIC
+	help
+	  Support pin multiplexing control on MediaTek MT7620.
+	  The driver is controlled by a device tree node which contains
+	  the pin mux functions for each available pin groups.
+
 config PINCTRL_MT7628
 	bool "MediaTek MT7628 pin control driver"
 	select PINCTRL_MTMIPS