ALSA: hda - introduce snd_hda_jack_detect() and snd_hda_pin_sense()

This helps merge duplicate code.

v2: add snd_hda_jack_detect() and comments recommended by Takashi.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>