Proposed fix for oops on SIGINT in splat atomic:64-bit test.

Proposed fix for oops on SIGINT in splat atomic:64-bit test.

The threads in the splat atomic:64-bit test share the data structure
atomic_priv_t ap, which lives on the kernel stack of the splat user-space
utility.  If splat terminates before the threads, accesses to that memory
location by the other threads become invalid.  Splat synchronizes with
the threads with the call:

wait_event_interruptible(ap.ap_waitq, splat_atomic_test1_cond(&ap, i));

Apparently, the SIGINT wakes and terminates splat prematurely, so that
GPFs or other bad things happen when the threads subsequently access ap.
This commit prevents this by using the uninterruptible form:

wait_event(ap.ap_waitq, splat_atomic_test1_cond(&ap, i));