MIPS: ralink: adds support for MT7620 SoC family

Add support code for mt7620 SOC.

The code detects the SoC and registers the clk / pinmux settings.

Signed-off-by: John Crispin <blogic@openwrt.org>
Acked-by: Gabor Juhos <juhosg@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5177/
diff --git a/arch/mips/ralink/Kconfig b/arch/mips/ralink/Kconfig
index ce57d3e..86f6c77 100644
--- a/arch/mips/ralink/Kconfig
+++ b/arch/mips/ralink/Kconfig
@@ -20,6 +20,9 @@
 		select USB_ARCH_HAS_OHCI
 		select USB_ARCH_HAS_EHCI
 
+	config SOC_MT7620
+		bool "MT7620"
+
 endchoice
 
 choice