patch from intel-drm-staging for 2.6.39

[Frederik Himpe]

This commit from intel-drm-staging fixes an oops for me when docking my 
system. Can it be added to 2.6.39?

commit c60001b9921a869c7dc916e72a22c5805cc562ae
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Fri Apr 22 10:47:08 2011 +0100

    drm: Take lock around probes for drm_fb_helper_hotplug_event

-- 
Frederik Himpe