drm/i915: Don't use GEN6_RC_VIDEO_FREQ on gen10+

GEN6_RC_VIDEO_FREQ is deprecated for >= gen10;
don't try to program it.

v2: Use IS_GEN9() instead of INTEL_GEN() and remove comment (Rodrigo)
Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171117080146.20150-1-david.weinehall@linux.intel.com

drivers/gpu/drm/i915/intel_pm.c

@@ -6602,9 +6602,10 @@ static void gen9_enable_rps(struct drm_i915_private *dev_priv)
 {
 	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
 
-	/* Program defaults and thresholds for RPS*/
-	I915_WRITE(GEN6_RC_VIDEO_FREQ,
-		GEN9_FREQUENCY(dev_priv->gt_pm.rps.rp1_freq));
+	/* Program defaults and thresholds for RPS */
+	if (IS_GEN9(dev_priv))
+		I915_WRITE(GEN6_RC_VIDEO_FREQ,
+			GEN9_FREQUENCY(dev_priv->gt_pm.rps.rp1_freq));
 
 	/* 1 second timeout*/
 	I915_WRITE(GEN6_RP_DOWN_TIMEOUT,