platform/x86: intel_skl_int3472: Move to intel/ subfolder

Start collecting Intel x86 related drivers in its own subfolder.
Move intel_skl_int3472 first.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210618125516.53510-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>