ASoC: SOF: Intel: ICL: add Icelake SSP count

On Icelake we have 6 SSP ports, add ICL SSP count to
enable all SSPs, instead of using the SSP count defined
for CNL.

Signed-off-by: Zhu Yingjiang <yingjiang.zhu@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>