ALSA: hda/realtek - Add headset Mic support for new Dell machine

Dell has new machines. It supports headset Mic and Headphone Mic.

Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>