kern/127441: [dtrace] Dtrace timestamp variable is wrapping as if define as uint32_t

[Thomas Backman]

Could we have this patch merged in time for 8.0? I don't know if the  
problems in the PR followups are big enough, but considering that the  
current implementation is horribly broken for everyone, and the patch  
fixes it for a large number of people, I don't really see the downside  
in merging it for the time being.

Regards,
Thomas