GPIO Pin Hold is not supported

[bugadani]

No description provided.

[bjoernQ]

For S3 (looks like most? others)

For C6

While I can imagine to have a FrozenPin driver (name is subject to bike-shedding) the

• Or users can set PMU_TIE_HIGH_HP_PAD_HOLD_ALL to maintain the input/output status of all
  digital pins
• Or users can set PMU_TIE_HIGH_LP_PAD_HOLD_ALL to hold the values of all LP pins, and set
  PMU_TIE_LOW_LP_PAD_HOLD_ALL to disable the hold function of all LP pins.

part makes things a bit more complex, but I still think supporting this in future can be done in a non-breaking way