add pintrl common files

[yvettewu1]

This is a common pinctrl file.
Can set/clear more multi-function pinctrl bits in this file.

[rusty1968]

Is this unit testable or it relies on other libs?

[lxuxx]

Is this unit testable or it relies on other libs?

This is used to program SCU registers to enable certain functions. It needs to be tested with corresponding modules that it enabled.

[yvettewu1]

@rusty1968 This unit is to set/clear the SCU pinctrl bits, which is not depending on other libs for that matter. It can be tested to see if it sets/clears the correct bits.

[yvettewu1]

@rusty1968 Other libs depend on this module to set/clear their corresponding pinmux, so we need this to be reviewed and push first.