ASoC: Intel: Skylake: Remove dfw config and associated structures

The skl_dfw_config structure is no longer required as the module
config is populated by parsing and reading the token values.

So, remove the structure.

Signed-off-by: Shreyas NC <shreyas.nc@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>