drm/i915: Don't program DSPCLK_GATE_D twice on IVB and VLV

We were programming register 0x42020 twice on those platforms. Once
should be enough.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -3498,11 +3498,8 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int pipe;
-	uint32_t dspclk_gate = ILK_VRHUNIT_CLOCK_GATE_DISABLE;
 	uint32_t snpcr;
 
-	I915_WRITE(ILK_DSPCLK_GATE_D, dspclk_gate);
-
 	I915_WRITE(WM3_LP_ILK, 0);
 	I915_WRITE(WM2_LP_ILK, 0);
 	I915_WRITE(WM1_LP_ILK, 0);
@@ -3580,9 +3577,6 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int pipe;
-	uint32_t dspclk_gate = ILK_VRHUNIT_CLOCK_GATE_DISABLE;
-
-	I915_WRITE(ILK_DSPCLK_GATE_D, dspclk_gate);
 
 	I915_WRITE(WM3_LP_ILK, 0);
 	I915_WRITE(WM2_LP_ILK, 0);