sync: reorder sync_fence_release

Previously fence's pts were freed before the were the fence was removed from the
global fence list.  This led to a race with the debugfs support where it would
iterate over sync_pts that had been freed.

Signed-off-by: Erik Gilling <konkers@android.com>
Change-Id: Ia3ddbf77de42ca593fc2dc353b5d04e42ddf3946