drm/i915: fix intel_ddi_get_cdclk_freq for ULT machines

For now, this code is just used by the eDP AUX channel frequency.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1161,6 +1161,8 @@ struct drm_i915_file_private {
 #define IS_VALLEYVIEW(dev)	(INTEL_INFO(dev)->is_valleyview)
 #define IS_HASWELL(dev)	(INTEL_INFO(dev)->is_haswell)
 #define IS_MOBILE(dev)		(INTEL_INFO(dev)->is_mobile)
+#define IS_ULT(dev)		(IS_HASWELL(dev) && \
+				 ((dev)->pci_device & 0xFF00) == 0x0A00)
 
 /*
  * The genX designation typically refers to the render engine, so render

drivers/gpu/drm/i915/intel_ddi.c

@@ -1309,6 +1309,8 @@ int intel_ddi_get_cdclk_freq(struct drm_i915_private *dev_priv)
 	else if ((I915_READ(LCPLL_CTL) & LCPLL_CLK_FREQ_MASK) ==
 		 LCPLL_CLK_FREQ_450)
 		return 450;
+	else if (IS_ULT(dev_priv->dev))
+		return 338;
 	else
 		return 540;
 }