ASoC: rt5682: Add the field "is_sdw" of private data

The field "is_sdw" is used for distinguishing the driver whether is run
in soundwire mode or not. That will run the separated setting in runtime
to make sure the driver can be run with the same build between i2s mode
and soundwire mode.

Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
Link: https://lore.kernel.org/r/980b97e1ab9c4fab8bd345ec2158f1fd@realtek.com


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