Can someone MFC usb/234503

[Mel Pilgrim]

The patch was committed to head on March 11 and flagged for MFC, but it 
hasn't be merged to stable yet.  I've been running this modification on 
11.2-R and 12.0-R using the affected devices as system disks for a 
little over two months without issue.  Can someone merge this into 
stable/11 and stable/12?  It's important (to me, at least) that it make 
it into 11.3-R, and the slush for it isn't far off.