ASoC: rt5682: fix unmet dependencies

The rt5682 code can be used in I2C or SoundWire mode. When I2C is not
selected, we have the following issue:

WARNING: unmet direct dependencies detected for SND_SOC_RT5682
  Depends on [n]: SOUND [=m] && !UML && SND [=m] && SND_SOC [=m] &&
  I2C [=n]
  Selected by [m]:
  - SND_SOC_RT5682_SDW [=m] && SOUND [=m] && !UML && SND [=m] &&
    SND_SOC [=m] && SOUNDWIRE [=m]

Fix by adding SOUNDWIRE as a dependency.

Fixes: 03f6fc6d ('ASoC: rt5682: Add the soundwire support')
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Oder Chiou <oder_chiou@realtek.com>
Link: https://lore.kernel.org/r/20200310163509.14466-2-pierre-louis.bossart@linux.intel.com


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