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Distributions such as Fedora, Ubuntu and Gallium don't currently
have a means to support Baytrail Chromebooks and other platforms
with the same build [1][2] due to incompatible platform drivers.

Add MCLK management to reuse this machine driver for Baytrail
platforms and solve this coexistence problem at last. UCM files are
provided at [3] and will eventually be submitted to the new repo.

The legacy byt-max98090 machine driver is still maintained but can
only be used when the other Atom/DPCM driver is not compiled in, or
when users don't want to configure extra mixers required by the
Atom/sst driver.

Tested on Lenovo 100s Baytrail Chromebook w/ Mr. Chromebox BOOT_STUB
firmware and Acer R11 Cherrytrail Chromebook

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1335196
[2] http://mailman.alsa-project.org/pipermail/alsa-devel/2016-August/
111641.html
[3] https://github.com/plbossart/UCM/tree/master/byt-max98090

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>