drm: dp helper: extract drm_dp_channel_eq_ok

radeon and intel use the exact same definition.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index fe06148..9e10420 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -322,4 +322,9 @@
 int
 i2c_dp_aux_add_bus(struct i2c_adapter *adapter);
 
+
+#define DP_LINK_STATUS_SIZE	   6
+bool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+			  int lane_count);
+
 #endif /* _DRM_DP_HELPER_H_ */