drm/i915: Fix CRC support for DP port D on CHV

Add the missing CRC control register value for DP port D on CHV.
Untested as I don't have a CHV machine with DP on port D.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Add a check to only allow DP D on chv, not vlv.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3100,6 +3100,12 @@ static int vlv_pipe_crc_ctl_reg(struct drm_device *dev,
 		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_VLV;
 		need_stable_symbols = true;
 		break;
+	case INTEL_PIPE_CRC_SOURCE_DP_D:
+		if (!IS_CHERRYVIEW(dev))
+			return -EINVAL;
+		*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_D_VLV;
+		need_stable_symbols = true;
+		break;
 	case INTEL_PIPE_CRC_SOURCE_NONE:
 		*val = 0;
 		break;