[PATCH v5 00/12] enhance DT support on gpio pxa

[Haojian Zhuang]

Changelog:

v5:
* Replace of_find_property() by of_property_read_bool().
* Rename __gpio_is_occupied() & __gpio_is_inverted().
* Avoid to use pxachip as variable name. Use chip instead.

v4:
* Re-oragnize these patches.
* Append document for new properties binding.
* Discard the full support on irq domain. It will be appended in other
  series.

v3:
* Fix the gpio irq issue on legacy platform.
* Discard irq_base & use irq domain instead in pxa_gpio_chip structure.
* Update DTS file since it's depend on latest pinctrl single driver.

v2:
* Fix the build issue without CONFIG_OF
* Append to check PINCTRL_SINGLE because of arch pxa not moved to DT
* Use bool for inverted, ed_mask, gafr variable