ASoC: Intel: Skylake: Unassign ram_read and read_write ops

Skylake driver makes no use of ram_read or ram_write operation so remove
the assignments. This prepares sound/soc/common/sst-dsp* for following
removal of unused DSP operations.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@intel.com>
Link: https://lore.kernel.org/r/20201006064907.16277-8-cezary.rojewski@intel.com


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