ASoC: rt5640: Add RT5642 ACPI ID for Intel Baytrail

Asus T100TAF uses ACPI ID "10EC5642" for its audio codec. I suppose it is
updated ACPI ID for the RT5642 codec since some earlier platforms are using
"10EC5640" with the RT5642 too.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>