ASoC: SOF: Intel: hda: Add iDisp4 DAI

ASoC: SOF: Intel: hda: Add iDisp4 DAI

commit e68d6696575e1af3f92125e842f2853708f34589 upstream.

TGL supports more than three iDisp DAI's.
Add support for iDisp4 CPU DAI.

Without this patch, we saw the below error on our TGL DUT:
   sof_rt5682 tgl_max98357a_rt5682: ASoC: CPU DAI iDisp4 Pin not registered

Signed-off-by: Sathyanarayana Nujella <sathyanarayana.nujella@intel.com>
Signed-off-by: Jairaj Arava <jairaj.arava@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191220171037.10689-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>