ALSA: hda - clean up CX20549 test mixer setup

name pins consistently (MIC1/LINE1/HP-OUT/CD) on all controls
affecting those pins.

remove duplicate SET_AMP_GAIN_MUTE to 0x17/index 0 and 0x17/index 1

really select MIC1, not Mixer out for recording

"Mixer out" for recording is not a "pin", adjust comment

Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>