Asus T100 internal microphone is not digital but analogue connected to IN1P
pin of the RT564x codec with shared bias between internal and headset
microphones. Because of this there is need to have machine specific DAPM
routes in byt-rt5640.

Add handling for them with the help of DMI quirk that is used to add custom
routes in addition to common. Because "Internal Mic" connected to DMIC1 is
not common to all move it as a default custom route when there is no match
in quirk table.

Custom "Internal Mic" -> "IN1P" with MICBIAS1 route is added for Asus T100.
Signed-off-by: NJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: NMark Brown <broonie@kernel.org>