staging/lustre/libcfs: Fix kstrtouint return value check fix

Apparently kstrtouint could return not just -EINVAL, but also -ERANGE,
so make sure we just check the return value for something negative.

Noticed by Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/libcfs/debug.c

@@ -185,7 +185,7 @@ static int param_set_uint_minmax(const char *val,
 	if (!val)
 		return -EINVAL;
 	ret = kstrtouint(val, 0, &num);
-	if (ret == -EINVAL || num < min || num > max)
+	if (ret < 0 || num < min || num > max)
 		return -EINVAL;
 	*((unsigned int *)kp->arg) = num;
 	return 0;