ALSA: hda - unmute pin amplifier in infoframe setup for Haswell

When Gfx driver reconnects a port and transcoder, the pin amplifier will
be muted. To enable sound, the pin amp need to be unmuted.

This patch
- moves pin amp unmuting from stream preparing to hdmi_setup_audio_infoframe().
  So if port:transcoder reconnection happens during stream playback, the ELDV
  unsol event can stil trigger pin's amp unmuting when re-setting up audio
  info frame.

- remove reading pin amp status before unmuting for speed-up, since pin amp
  should always be unmuted.

- rename haswell_verify_pin_D0() to haswell_verify_D0(), since the convertor
  power state is also fixed here.

This patch is mostly based on suggestion of David Henningsson.

Cc: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>