drm/i915/dg1: Fix power gate sequence.

sub-pipe PG is not present on DG1. Setting these bits can disable
other power gates and cause GPU hangs on video playbacks.

VLK: 16314, 4304

Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13381
Fixes: 85a12d7 ("drm/i915/tgl: Fix Media power gate sequence.")
Cc: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241219210019.70532-1-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
(cherry picked from commit de70619)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>

Author: rodrigovivi

drivers/gpu/drm/i915/gt/intel_rc6.c

@@ -133,7 +133,7 @@ static void gen11_rc6_enable(struct intel_rc6 *rc6)
 			GEN9_MEDIA_PG_ENABLE |
 			GEN11_MEDIA_SAMPLER_PG_ENABLE;
 
-	if (GRAPHICS_VER(gt->i915) >= 12) {
+	if (GRAPHICS_VER(gt->i915) >= 12 && !IS_DG1(gt->i915)) {
 		for (i = 0; i < I915_MAX_VCS; i++)
 			if (HAS_ENGINE(gt, _VCS(i)))
 				pg_enable |= (VDN_HCP_POWERGATE_ENABLE(i) |