ALSA: hda - Consolidate add_in_jack_modes and add_out_jack_modes hints

There is no big merit to distinguish these two hints.  Instead, just
have a single flag, add_jack_modes, for creating the jack mode enum
ctls for both I/O directions.

The hint string parser code is left and translated as add_jack_modes
just for keeping compatibility.

Signed-off-by: Takashi Iwai <tiwai@suse.de>