Fix a typo referencing an incorrect symbol

The splat_taskq_test4_common function was incorrectly referencing
the splat_taskq-test13_func symbol, when it meant to be using the
splat_taskq_test4_func symbol.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#61

module/splat/splat-taskq.c

@@ -344,7 +344,7 @@ splat_taskq_test4_common(struct file *file, void *arg, int minalloc,
 				splat_vprint(file, SPLAT_TASKQ_TEST4_NAME,
 				        "Taskq '%s' function '%s' dispatch "
 					"%d failed\n", tq_arg.name,
-					sym2str(splat_taskq_test13_func), j);
+					sym2str(splat_taskq_test4_func), j);
 					rc = -EINVAL;
 					goto out;
 			}