Due to the recent change for multiple HP as line-out switch, only
one of the multiple headphons (usually a wrong one) is toggled
and the other pins are still disabled. This causes the silent output
problem on some Dell laptops.
Also, the hp_switch check is screwed up when a line-in or a mic-in
jack exists. This is added as an additional output, but hp_switch
check doesn't take it into account.
This patch fixes these issues: simplify hp_switch check by using
the NID instead of bool, and clean up / fix the toggle of HP pins
in unsol event handler code.