drm/i915: Remove intel_psr_is_enabled function.

This function was in use to check if PSR feature got enabled.
However on HSW and BDW we currently force psr exit by disabling
EDP_PSR_ENABLE bit at EDP_PSR_CTL(dev). So this function was actually
returning the active/inactive state that is different from the enable/disable
meaning and had the risk of false negative.

But anyway this check with DRRS was dangerous, since DRRS could try to get enabled
before PSR gets there. So let's just remove it for now.
A proper synchronization mechanism must be implemented later probably
using pipe config.

Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -4763,14 +4763,9 @@ void intel_dp_set_drrs_state(struct drm_device *dev, int refresh_rate)
 	}
 
 	/*
-	 * FIXME: This needs proper synchronization with psr state. But really
-	 * hard to tell without seeing the user of this function of this code.
-	 * Check locking and ordering once that lands.
+	 * FIXME: This needs proper synchronization with psr state for some
+	 * platforms that cannot have PSR and DRRS enabled at the same time.
 	 */
-	if (INTEL_INFO(dev)->gen < 8 && intel_psr_is_enabled(dev)) {
-		DRM_DEBUG_KMS("DRRS is disabled as PSR is enabled\n");
-		return;
-	}
 
 	encoder = intel_attached_encoder(&intel_connector->base);
 	intel_dp = enc_to_intel_dp(&encoder->base);

drivers/gpu/drm/i915/intel_drv.h

@@ -1115,7 +1115,6 @@ void intel_backlight_unregister(struct drm_device *dev);
 
 
 /* intel_psr.c */
-bool intel_psr_is_enabled(struct drm_device *dev);
 void intel_psr_enable(struct intel_dp *intel_dp);
 void intel_psr_disable(struct intel_dp *intel_dp);
 void intel_psr_invalidate(struct drm_device *dev,

drivers/gpu/drm/i915/intel_psr.c

@@ -61,16 +61,6 @@ static bool is_edp_psr(struct intel_dp *intel_dp)
 	return intel_dp->psr_dpcd[0] & DP_PSR_IS_SUPPORTED;
 }
 
-bool intel_psr_is_enabled(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (!HAS_PSR(dev))
-		return false;
-
-	return I915_READ(EDP_PSR_CTL(dev)) & EDP_PSR_ENABLE;
-}
-
 static void intel_psr_write_vsc(struct intel_dp *intel_dp,
 				    struct edp_vsc_psr *vsc_psr)
 {