ASoC: SOF - remove the dead code (skylake/kabylake)

ASoC: SOF - remove the dead code (skylake/kabylake)

Appearently the CONFIG_SND_SOC_SOF_KABYLAKE and CONFIG_SND_SOC_SOF_SKYLAKE
options are not present in Kconfig and 'struct snd_sof_dsp_ops sof_skl_ops'
is not declared in the code, too.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20191028173329.29538-1-perex@perex.cz
Signed-off-by: Mark Brown <broonie@kernel.org>