ipmi_ssif: Use interruptible completion for waiting in the thread
ipmi_ssif: Use interruptible completion for waiting in the thread

The code was using an normal completion, but that caused stuck
task errors after a while.  Use an interruptible one to avoid that.

Signed-off-by: Corey Minyard <97c9634d4bed2779ee3e53c0495565ccc28c2363@mvista.com>

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