linux(4): Replace casuword32 by casueword32.

Follow the r349951 (30b3018d), add check to react to stops and requests
to terminate between retries.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D31254
MFC after: 2 weeks

(cherry picked from commit 4f34dc64536f7de8324ca1a494aee88e64c7de70)