drm/i915/skl: Query display address through a wrapper

Need to do this in order to support 90/270 rotated display.

v2: Pass in drm_plane instead of plane index to intel_obj_display_address.

v3:
    * Renamed intel_obj_display_address to intel_plane_obj_offset.
      (Chris Wilson)
    * Simplified rotation check to bitwise AND. (Chris Wilson)

v4:
    * Extracted 90/270 rotation check into a helper function. (Michel Thierry)

v5:
    * Rebased for ggtt view changes.

For: VIZ-4545
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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 cb00bd0..db0e7bf 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -988,6 +988,12 @@
 intel_tile_height(struct drm_device *dev, uint32_t pixel_format,
 		  uint64_t fb_format_modifier);
 
+static inline bool
+intel_rotation_90_or_270(unsigned int rotation)
+{
+	return rotation & (BIT(DRM_ROTATE_90) | BIT(DRM_ROTATE_270));
+}
+
 /* shared dpll functions */
 struct intel_shared_dpll *intel_crtc_to_shared_dpll(struct intel_crtc *crtc);
 void assert_shared_dpll(struct drm_i915_private *dev_priv,
@@ -1042,6 +1048,9 @@
 void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc);
 void intel_modeset_preclose(struct drm_device *dev, struct drm_file *file);
 
+unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
+				     struct drm_i915_gem_object *obj);
+
 /* intel_dp.c */
 void intel_dp_init(struct drm_device *dev, int output_reg, enum port port);
 bool intel_dp_init_connector(struct intel_digital_port *intel_dig_port,