ASoC: codecs: max98373: split I2C and common parts

To prepare support for SoundWire, let's first split the I2C and common
parts. No new functionality, just indents and formatting to make
checkpatch happy.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200708203215.231776-2-pierre-louis.bossart@linux.intel.com


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