ASoC: Intel: Skylake: use hda_bus instead of hdac_bus

Use hda_bus instead of hdac_bus in the SKL ASoC platform driver to enable
reuse of legacy HDA codec drivers.

Signed-off-by: Rakesh Ughreja <rakesh.a.ughreja@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>