ASoC: Intel: Skylake: Unstatify skl_dsp_enable_core

The function skl_dsp_enable_core will be called by other parts of
driver so this can no longer be a static function.

Signed-off-by: Jayachandran B <jayachandran.b@intel.com>
Signed-off-by: GuruprasadX Pawse <guruprasadx.pawse@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>