[ALSA] hda-codec - Fix auto-probe of ALC880

Modules: HDA Codec driver

This patch is to fix the problem of calculating the nid incorrectly
when auto-probe for ALC880. The problem to be fixed often behaves
with such words when using dmesg, 'num_steps = 0 for NID=0x8' when
auto-probe for ALC880.

The patch contains:
- alsa-kernel/pci/hda/patch_realtek.c: replace 'alc880_dac_to_idx'
  with 'alc880_idx_to_dac' in function 'alc880_auto_fill_dac_nids()'

Signed-off-by: Libin Yang <libin.yang@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>