pine64-pinephone: align more closely to ALSA UCM specification (MR 1204)

Some of the recommendations have changed upstream and a few devices
should be called differently now. The following changes are made:

  - Headphone -> Headphone*s*
    (https://github.com/alsa-project/alsa-lib/blob/29041c522071172af2c6bf086b3a0c19510a6660/include/use-case.h#L136)
  - DigitalMic -> Mic
    (https://github.com/alsa-project/alsa-lib/commit/1ad660ddeecb2a364f1ca62aa60f256f7029cfdc)
  - HeadsetMic -> Headset
    (https://github.com/alsa-project/alsa-lib/blob/29041c522071172af2c6bf086b3a0c19510a6660/include/use-case.h#L137)
  - Add .conf suffix for verb configurations
  - Set Playback/CaptureChannels as integer, not as string
  - Remove empty Enable/DisableSequence sections
    (https://github.com/alsa-project/alsa-ucm-conf/commit/d6a150d34f6e3a327215ad3452cfcfe164671717)