pinctrl: pinctrl-imx: add imx51 pinctrl driver

ChangeLog v1->v2:
* change PIN_FUNC_ID base in binding doc to 0 from 1.

Acked-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index da185de..515e32f 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -10,6 +10,7 @@
 endif
 obj-$(CONFIG_GENERIC_PINCONF)	+= pinconf-generic.o
 obj-$(CONFIG_PINCTRL_IMX)	+= pinctrl-imx.o
+obj-$(CONFIG_PINCTRL_IMX51)	+= pinctrl-imx51.o
 obj-$(CONFIG_PINCTRL_IMX53)	+= pinctrl-imx53.o
 obj-$(CONFIG_PINCTRL_IMX6Q)	+= pinctrl-imx6q.o
 obj-$(CONFIG_PINCTRL_PXA3xx)	+= pinctrl-pxa3xx.o