drm/i915: Populate output_types from .get_config()

Rather than having the caller of .get_config() set output_types based on
encoder->type, let's just have .get_config() itself populate
output_types. This way we are isolated from encoder->type, which won't
be useable for this purpose anyway soon (at least for DDI encoders).

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171027193128.14483-2-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/intel_lvds.c

@@ -125,6 +125,8 @@ static void intel_lvds_get_config(struct intel_encoder *encoder,
 	struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
 	u32 tmp, flags = 0;
 
+	pipe_config->output_types |= BIT(INTEL_OUTPUT_LVDS);
+
 	tmp = I915_READ(lvds_encoder->reg);
 	if (tmp & LVDS_HSYNC_POLARITY)
 		flags |= DRM_MODE_FLAG_NHSYNC;