ASoC: Intel: Atom: add support for RT5642

The machine driver is not loaded when the BIOS uses the 10EC5642
_HID. Add it to the white list of known _HIDs, codec_name is
already taken care of by previous commit

Tested on Asus T100TAF.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>