Dont create input devices for phantom jacks.

Here, we extend snd_jack_new() to support phantom jack creating:
pass in a bool param for [non-]phantom flag, and a bool param
initial_jack to indicate whether we need to create a kctl at
this stage.

We can also add a kctl to the jack after its created meaning we
can now integrate the HDA and ASoC jacks.
Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>