[media] media: Add ALSA Media Controller function entities

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: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>