drm/i915: Export the generic, not arch specific, intel_update_watermarks()

Rather than export every single architecture specific update_wm, just
export the wrapper around the display vtable.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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 79cabf5..8748e5e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -422,7 +422,7 @@
 extern void intel_cpt_verify_modeset(struct drm_device *dev, int pipe);
 
 /* For use by IVB LP watermark workaround in intel_sprite.c */
-extern void sandybridge_update_wm(struct drm_device *dev);
+extern void intel_update_watermarks(struct drm_device *dev);
 extern void intel_update_sprite_watermarks(struct drm_device *dev, int pipe,
 					   uint32_t sprite_width,
 					   int pixel_size);