ASoC: Add initial ZL38060 driver

The ZL38060 is a "Connected Home Audio Processor" from Microsemi,
which consists of a Digital Signal Processor (DSP), several Digital
Audio Interfaces (DAIs), analog outputs, and a block of 14 GPIOs.

This driver supports only a tiny subset of the chip's functionality
and possible configurations:
- bypass mode (whole dsp block is bypassed)
- chip's I2S DAI routed directly to/from DACs and microphone
- chip's internal clock is driven by a 12 MHz external crystal
- chip's DAI connected to CPU is I2S, and bit + frame clock master
- chip must be strapped for "host boot": in this mode, firmware will
  be provided by this driver.

Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Link: https://lore.kernel.org/r/20200417221341.31428-2-TheSven73@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>