soc/intel/skylake: Use common opregion implementation

Enable SOC_INTEL_COMMON_GFX_OPREGION for all FSP versions.
Allows to get rid of opregion.c, as it's no longer needed.

Change-Id: I39190488e12917a09dbf7ee3947a33940ebc290b
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/20222
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
5 files changed