Currently VIA driver controls the power-state of each pin per jack
detection.  But, it means that the power-state mismatch may occur when
the machine doesn't give the proper jack-detection.

For avoiding this problem, a new control element "Dynamic Power-Control"
is provided so that user can turn on/off the pin-power control.
Signed-off-by: Takashi Iwai <tiwai@suse.de>