kernel/hung_task.c: convert simple_strtoul to kstrtouint

sysctl_hung_task_panic has been changed to unsigned int.  use kstrtouint
instead of obsolete simple_strtoul
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/hung_task.c

@@ -52,8 +52,10 @@ unsigned int __read_mostly sysctl_hung_task_panic =
 
 static int __init hung_task_panic_setup(char *str)
 {
-	sysctl_hung_task_panic = simple_strtoul(str, NULL, 0);
+	int rc = kstrtouint(str, 0, &sysctl_hung_task_panic);
 
+	if (rc)
+		return rc;
 	return 1;
 }
 __setup("hung_task_panic=", hung_task_panic_setup);