counter: 104-quad-8: Make quad8_ops static

Fix sparse warning:

drivers/counter/104-quad-8.c:836:26: warning:
 symbol 'quad8_ops' was not declared. Should it be static?
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/counter/104-quad-8.c

@@ -833,7 +833,7 @@ static int quad8_action_get(struct counter_device *counter,
 	return 0;
 }
 
-const struct counter_ops quad8_ops = {
+static const struct counter_ops quad8_ops = {
 	.signal_read = quad8_signal_read,
 	.count_read = quad8_count_read,
 	.count_write = quad8_count_write,