OF: pinctrl: MIPS: lantiq: implement lantiq/xway pinctrl support

Implement support for pinctrl on lantiq/xway socs. The IO core found on these
socs has the registers for pinctrl, pinconf and gpio mixed up in the same
register range. As the gpio_chip handling is only a few lines, the driver also
implements the gpio functionality. This obseletes the old gpio driver that was
located in the arch/ folder.

Signed-off-by: John Crispin <blogic@openwrt.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 331d574..b0f74b8 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -241,6 +241,8 @@
 	select HAVE_MACH_CLKDEV
 	select CLKDEV_LOOKUP
 	select USE_OF
+	select PINCTRL
+	select PINCTRL_LANTIQ
 
 config LASAT
 	bool "LASAT Networks platforms"