ALSA: hda - detect jacks on VT1708 even when no streams are active

These days, GUIs such as Gnome sound settings want to be able to
show the correct jack status even when no streams are currently
running. I doubt this gives any measurable difference in power,
but if it does, the "Jack Detect" control can still be used to
turn polling off.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>