platform/x86: intel_int0002_vgpio: Get rid of custom ICPU() macro

Replace custom grown macro with generic INTEL_CPU_FAM6() one.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>