drm/core: Fix old_fb handling in pan_display_atomic.
drm/core: Fix old_fb handling in pan_display_atomic.

Don't touch plane->old_fb/fb without having the right locks held.

Signed-off-by: Maarten Lankhorst <743c2818a341d71b99ed2b566f9f80c2fc288f93@linux.intel.com>
Reviewed-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>
Signed-off-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>
Link: e0fe5e5a8c5075def69d8df5939e4e7bacada46e@ubuntu.com

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs