pinctrl: Add Intel Keem Bay pinctrl driver

About Intel Keem Bay:
-------------------
Intel Keem Bay is a computer vision AI accelerator SoC based on ARM CPU.
Documentation of Keem Bay: Documentation/vpu/vpu-stack-overview.rst.

Pinctrl IP:
----------
The SoC has a customised pinmux controller IP which controls pin
multiplexing and configuration.

Keem Bay pinctrl IP is not based on and have nothing in common with the
existing pinctrl drivers. The registers used are incompatible with the
existing drivers, so it requires a new driver.

Add pinctrl driver to enable pin control support in the Intel Keem Bay SoC.

Co-developed-by: Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Signed-off-by: Vineetha G. Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Co-developed-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@intel.com>
Signed-off-by: Lakshmi Sowjanya D <lakshmi.sowjanya.d@intel.com>
Reviewed-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210806142527.29113-3-lakshmi.sowjanya.d@intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>