ALSA: hda - add basic jack reporting functions to patch_conexant.c

Added functions to report jack sense.
As CXT5051_PORTB_EVENT has the same value as CONEXANT_MIC_EVENT two input
devices for the microphone will be created if using CXT5051.

Signed-off-by: Ulrich Dangel <uli@spamt.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>