mv_xor: fix race in tasklet function

use mv_xor_slot_cleanup() instead of __mv_xor_slot_cleanup() as the former function
aquires the spin lock that needed to protect the drivers data.

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

drivers/dma/mv_xor.c

@@ -449,7 +449,7 @@ mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan)
 static void mv_xor_tasklet(unsigned long data)
 {
 	struct mv_xor_chan *chan = (struct mv_xor_chan *) data;
-	__mv_xor_slot_cleanup(chan);
+	mv_xor_slot_cleanup(chan);
 }
 
 static struct mv_xor_desc_slot *