ASoC: Intel: Fix Kconfig with top-level selector

Follow network example suggested by Linus, move Intel definitions
in if/endif block and clarify in help text which options distro
configurations should enable - everything except legacy Baytrail stuff and
NOCODEC (test only)

To avoid user confusion, machine drivers are handled with a submenu made
dependent on this top-level selector.

There should be no functionality change - except that sound capabilities
are restored when using older configs without any user selection.

Note that the SND_SOC_ACPI_INTEL_MATCH config is currently filtered
out by the top-level selector. This will change in the near future to
allow for this option to be selected by both SST and SOF drivers

(simplification with submenu for machine drivers by Vinod Koul)

Fixes: f6a118a8 ("ASoC: Intel: clarify Kconfig dependencies")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>