platform/x86: intel/pmc: Relocate Ice Lake PCH support

Create icl.c for Ice Lake PCH specific structures and init().
This file supports Ice Lake, Ice Lake NNPI and Jasper Lake platforms.
There are no functional changes involved.

Cc: David E Box <david.e.box@linux.intel.com>
Reviewed-by: "David E. Box" <david.e.box@linux.intel.com>
Signed-off-by: Xi Pardee <xi.pardee@intel.com>
Signed-off-by: "David E. Box" <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20221114183257.2067662-6-gayatri.kammela@linux.intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>