ALSA: hda - Fix bad dereference of jack object

The hda_jack_tbl entries are managed by snd_array for allowing
multiple jacks.  It's good per se, but the problem is that struct
hda_jack_callback keeps the hda_jack_tbl pointer.  Since snd_array
doesn't preserve each pointer at resizing the array, we can't keep the
original pointer but have to deduce the pointer at each time via
snd_array_entry() instead.  Actually, this resulted in the deference
to the wrong pointer on codecs that have many pins such as CS4208.

This patch replaces the pointer to the NID value as the search key.
As an unexpected good side effect, this even simplifies the code, as
only NID is needed in most cases.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>