drm/i915: add HAS_DDI check

And use it whenever we call code that uses the DDIs. We already have
intel_ddi.c and prefix every function with intel_ddi_something instead of
haswell_something, so I think replacing the checks with HAS_DDI makes more
sense. Just a cosmetical change, yes I know, but I have this OCD...

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d76258d..f290438 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -379,7 +379,7 @@
 	 * clock divider.
 	 */
 	if (is_cpu_edp(intel_dp)) {
-		if (IS_HASWELL(dev))
+		if (HAS_DDI(dev))
 			aux_clock_divider = intel_ddi_get_cdclk_freq(dev_priv) >> 1;
 		else if (IS_VALLEYVIEW(dev))
 			aux_clock_divider = 100;
@@ -1791,7 +1791,7 @@
 	int voltage_tries, loop_tries;
 	uint32_t DP = intel_dp->DP;
 
-	if (IS_HASWELL(dev))
+	if (HAS_DDI(dev))
 		intel_ddi_prepare_link_retrain(encoder);
 
 	/* Write the link configuration data */
@@ -1981,7 +1981,7 @@
 	 *   intel_ddi_prepare_link_retrain will take care of redoing the link
 	 *   train.
 	 */
-	if (IS_HASWELL(dev))
+	if (HAS_DDI(dev))
 		return;
 
 	if (WARN_ON((I915_READ(intel_dp->output_reg) & DP_PORT_EN) == 0))
@@ -2742,7 +2742,7 @@
 	intel_connector_attach_encoder(intel_connector, intel_encoder);
 	drm_sysfs_connector_add(connector);
 
-	if (IS_HASWELL(dev))
+	if (HAS_DDI(dev))
 		intel_connector->get_hw_state = intel_ddi_connector_get_hw_state;
 	else
 		intel_connector->get_hw_state = intel_connector_get_hw_state;