ASoC: Intel: Kconfig: Simplify-clarify ACPI/PCI dependencies

PCI/ACPI selections should not happen in Kconfig for machine drivers,
move to SOC selections.

Add distinction between PCI and ACPI HiFi2 platforms and help text.

There should be no functionality change.

The PCI-based platforms may be removed at some point since Medfield
is not really supported by anyone, and with Edison now defunct support for
Merrifield/Edison is to be determined.

The dependency on SND_DMA_SGBUF for Haswell is not clear at this
point and may have to be further updated.

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