ASoC: intel: byt: Introduce new map for dual mics

The RT5651 codec has 3 analog inputs. Some laptops have two different
internal analog microphones on the external case.
Add a new custom quirk mapping the two internal mics on IN1P / IN2P,
leaving the headset mic on IN3P.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>