drm/i915: Drop early VLV WA to fix Voltage not getting dropped to Vmin

Drop WA to fix Voltage not getting dropped to Vmin when Gfx is power
gated for latest VLV revision.

Workaround fixed in Latest VLV revision. Forcing Gfx clk up not needed,
and Requesting the min freq should bring bring the voltage Vnn.

v2: Drop WA for Latest VLV revision (Ville)
Signed-off-by: Deepak S <deepak.s@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[Jani: modified code comment, reformatted the commit message a bit.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -3209,6 +3209,14 @@ void gen6_set_rps(struct drm_device *dev, u8 val)
 */
 static void vlv_set_rps_idle(struct drm_i915_private *dev_priv)
 {
+	struct drm_device *dev = dev_priv->dev;
+
+	/* Latest VLV doesn't need to force the gfx clock */
+	if (dev->pdev->revision >= 0xd) {
+		valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_freq_softlimit);
+		return;
+	}
+
 	/*
 	 * When we are idle.  Drop to min voltage state.
 	 */