drm/i915: Add HSW CRT output readout support

Call intel_ddi_get_config() to get the pipe_bpp settings from
DDI.

The sync polarity settings from DDI are irrelevant for CRT
output, so override them with data from the ADPA register.

v2: Extract intel_crt_get_flags()

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=69691
Tested-by: Qingshuai Tian <qingshuai.tian@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 7e9fa53..a43ac3a 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1269,8 +1269,8 @@
 		intel_dp_check_link_status(intel_dp);
 }
 
-static void intel_ddi_get_config(struct intel_encoder *encoder,
-				 struct intel_crtc_config *pipe_config)
+void intel_ddi_get_config(struct intel_encoder *encoder,
+			  struct intel_crtc_config *pipe_config)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);