ptp: clockmatrix: remove unnecessary comparison

The type of loaddr is u8 which is always '<=' 0xff, so the
loaddr <= 0xff is always true, we can remove this comparison.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Vincent Cheng <vincent.cheng.xh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>