drm/xe/gsc: Implement WA 14015076503

When the GSC FW is loaded, we need to inform it when a GSCCS reset is
coming and then wait 200ms for it to get ready to process the reset.

v2: move WA code to GSC file, use variable in Makefile (John)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <john.c.harrison@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>