On Asus MJ401TA (with Realtek ALC256), the headset mic is connected to
pin 0x19, with default configuration value 0x411111f0 (indicating no
physical connection).

Enable this by quirking the pin. Mic jack detection was also tested and
found to be working.

This enables use of the headset mic on this product.
Signed-off-by: Daniel Drake <drake@endlessm.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191017081501.17135-1-drake@endlessm.comSigned-off-by: Takashi Iwai <tiwai@suse.de>