ALSA: hda - Register chmap obj as priv data instead of codec

With this chmap object is added as private data and new ops are
added to access driver specific chmap.

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>