[PATCH v3 0/3] implement pinmux for arch-mmp

[Haojian Zhuang]

#1 & #2 patch are based on pinctrl/for-next branch.
#3 patch is based on arm-soc/for-next branch since it replies the new pxa-gpio
driver.

Changelog v3->v2:
1. Avoid to use number in groups definition. Use macro instead.
2. Replace func array with mux array. There's a risk of align func array
and group array. Both pin and mux are defined in new mux array.
3. Support gpio again in gpio-pxa.
4. If multiple pins can be configured to same GPIO pin, define new specific
gpio group.

Changelog v1->v2:
1. Split pxa3xx pinmux driver to more pieces.
2. Add PXA168/PXA910/PXA930/MMP2 silicon support.
3. Now only enable it in arch-mmp.
4. Now all predefined pins are enabled by default. Although some devices
are not used, they would be declared in arch-pxa. It would result define
unnecessary pins in platform.
5. Remove gpio support since it's depend on some gpio-pxa patches in
arm-soc trees.