ASoC: Create a generic Pi Hat WM8804 driver

Reduce the amount of duplicated code by creating a generic driver for
Pi Hat digi cards using the WM8804 codec.

This replaces the
Allo DigiOne, Hifiberry Digi/Pro, JustBoom Digi and IQAudIO Digi
dedicate soundcard drivers with a generic driver.

There are no significant changes to the runtime behavior of the drivers
and end users should not have to change any configuration settings
after upgrading.

Minor changes
* Check the return value of snd_soc_component_update_bits
* Added some pr_debug tracing
* Various checkpatch tidyups
* Updated allodigi-one to use use 128FS at > 96 Khz. This appears to
  be an omission in the original driver code so followed the Hifiberry
  DAC driver approach.