dmaengine: Revert "dmaengine: dmatest: Fix dmatest waiting less when interrupted"

Several issues with this change:

* The analysis is flawed and it's unclear what problem is being
fixed. There is no difference between wait_event_freezable_timeout()
and wait_event_timeout() with respect to device interrupts. And of
course "the interrupt notifying the finish of an operation happens
during wait_event_freezable_timeout()" -- that's how it's supposed
to work.

* The link at the "Closes:" tag appears to be an unrelated
use-after-free in idxd.

* It introduces a regression: dmatest threads are meant to be
freezable and this change breaks that.

See discussion here:
https://lore.kernel.org/dmaengine/[e-mail]/

Fixes: e87ca16e9911 ("dmaengine: dmatest: Fix dmatest waiting less when interrupted")
Signed-off-by: Nathan Lynch <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/dmatest.c

···
 		} else {
 			dma_async_issue_pending(chan);
 
-			wait_event_timeout(thread->done_wait,
-					   done->done,
-					   msecs_to_jiffies(params->timeout));
+			wait_event_freezable_timeout(thread->done_wait,
+					done->done,
+					msecs_to_jiffies(params->timeout));
 
 			status = dma_async_is_tx_complete(chan, cookie, NULL,
 							  NULL);