Add ALSA Media Controller capture, playback, and mixer
function entity defines.

[mchehab@osg.samsung.com: fix a trivial merge conflict and start
 MEDIA_ENT_AUDIO_F from 3000]
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>
Acked-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>