ioat: fix infinite timeout checking in ioat2_quiesce

Fix typo in ioat2_quiesce. check 'tmo' is zero, not 'end'.  Also applies
to 2.6.32.3

Cc: <stable@kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/ioat/dma_v2.c

@@ -249,7 +249,7 @@ int ioat2_quiesce(struct ioat_chan_common *chan, unsigned long tmo)
 	if (is_ioat_active(status) || is_ioat_idle(status))
 		ioat_suspend(chan);
 	while (is_ioat_active(status) || is_ioat_idle(status)) {
-		if (end && time_after(jiffies, end)) {
+		if (tmo && time_after(jiffies, end)) {
 			err = -ETIMEDOUT;
 			break;
 		}