platform/x86: intel_pmc_core: Fix PCH IP name

For Cannonlake and Icelake, the IP name for Res_6 should be SPF i.e.
South Port F. No functional change is intended other than just renaming
the IP appropriately.

Cc: "David E. Box" <david.e.box@intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Fixes: 291101f6

 ("platform/x86: intel_pmc_core: Add CannonLake PCH support")
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>