We should only select SND_INTEL_NHLT when ACPI is defined. This was
done for the legacy HDAudio driver but not for DSP-enabled cases,
leading to compilation errors with randconfig.

Fix by aligning on the same solution.

For the Skylake driver this is overkill since there is a top-level
dependency on ACPI, but it doesn't hurt and it's better to have
consistency.

Fixes: 68b953ae ('ASoC: SOF: Intel: hda: fixup HDaudio topology name with DMIC number')
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190829214213.11653-1-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>