chmap object represents multichannel capability and contains chmap
ops. Legacy driver is updated to use this.

With next set of patches chmap object is moved to common to be
reused by other drivers (ex: skylake ASoC hdmi driver).
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>