ALSA: hda/realtek - Finer tuning of auto-parser with badness evaluation

This patch improves the Realtek auto-parser for assigning the DACs and
mixers in more suitable ways by evaluating the assignment with "badness"
calculations.

When assigning a DAC hinders the assignment of individual DACs for
other pins, some badness point is given.  Similarly, when it blocks the
assignment of unique mixer controls, another badness point is added.
Also, if no DAC, even shared DAC, can be assigned, more badness is
pointed.  Finally, comparing the accumulated badness, the best route is
chosen among several trials.

Signed-off-by: Takashi Iwai <tiwai@suse.de>