The behavior of Nvidia HDMI codec regarding the pin-detection unsol events
is based on the old HD-audio spec, i.e. PD bit indicates only the update
and doesn't show the current state.  Since the current code assumes the
new behavior, the pin-detection doesn't work relialby with these h/w.

This patch adds a flag for indicating the old spec, and fixes the issue
by checking the pin-detection explicitly for such hardware.
Tested-by: NWei Ni <wni@nvidia.com>
Cc: <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>