drm/i915: Store max lane count in intel_digital_port

Rather than having open coded checks for the DDI A/E configuration,
just store the max supported lane count in intel_digital_port.

We had an open coded check for DDI A, but not for DDI E. So we may
have been vilating the DDI E max lane count.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 054aa76..d4ed7aa 100755
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -2033,6 +2033,11 @@
 	enum port port = intel_dig_port->port;
 	uint8_t alternate_ddc_pin;
 
+	if (WARN(intel_dig_port->max_lanes < 4,
+		 "Not enough lanes (%d) for HDMI on port %c\n",
+		 intel_dig_port->max_lanes, port_name(port)))
+		return;
+
 	drm_connector_init(dev, connector, &intel_hdmi_connector_funcs,
 			   DRM_MODE_CONNECTOR_HDMIA);
 	drm_connector_helper_add(connector, &intel_hdmi_connector_helper_funcs);
@@ -2218,6 +2223,7 @@
 	dev_priv->dig_port_map[port] = intel_encoder;
 	intel_dig_port->hdmi.hdmi_reg = hdmi_reg;
 	intel_dig_port->dp.output_reg = INVALID_MMIO_REG;
+	intel_dig_port->max_lanes = 4;
 
 	intel_hdmi_init_connector(intel_dig_port, intel_connector);
 }