ASoC: adds support for AMP4 Pro to the DAC Plus driver

The AMP4 Pro is a I2S master mode capable amplifier with
clean onboard clock generators.
We can share the card driver between TAS575x amplifiers
and the PCM512x DACs as they are SW compatible.
From a HW perspective though we need to limit the sample
rates to the standard audio rates to avoid running the
onboard clocks through the PLL. Using the PLL would require
even a different HW.
DAI/stream name are also set accordingly to allow the user
a convenient identification of the soundcard

Needs the pcm512x driver with TAS575x support (already in
upstream kernel).

Signed-off-by: Joerg Schambacher <joerg@hifiberry.com>