Uses the drm ELD core framework to apply rate and channel

Also compute the format to be set based on ELD.

Even though the channel constraint is based on ELD, infoframe
is set with stereo only. Multichannel support will be added
later.
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>