drm/i915: Create generic intel_panel for LVDS and eDP

Create a generic struct intel_panel for sharing a data structure and code
between eDP and LVDS panels. Add the new struct to intel_connector so that
later on we can have generic EDID and mode reading functions with EDID
caching that transparently fallback to fixed mode when EDID is not
available.

Add intel_panel as a dummy first, and move data (such as the mentioned
fixed mode) to it in later patches.

Based on earlier work by Chris Wilson <chris@chris-wilson.co.uk>

CC: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Fixup tiny conflict in intel_dp_destroy.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index fa388fd..b37bf28 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -163,6 +163,9 @@
 	int crtc_mask;
 };
 
+struct intel_panel {
+};
+
 struct intel_connector {
 	struct drm_connector base;
 	/*
@@ -179,6 +182,9 @@
 	/* Reads out the current hw, returning true if the connector is enabled
 	 * and active (i.e. dpms ON state). */
 	bool (*get_hw_state)(struct intel_connector *);
+
+	/* Panel info for eDP and LVDS */
+	struct intel_panel panel;
 };
 
 struct intel_crtc {
@@ -436,6 +442,9 @@
 				      enum plane plane);
 
 /* intel_panel.c */
+extern int intel_panel_init(struct intel_panel *panel);
+extern void intel_panel_fini(struct intel_panel *panel);
+
 extern void intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
 				   struct drm_display_mode *adjusted_mode);
 extern void intel_pch_panel_fitting(struct drm_device *dev,