Fixes the following sparse warning:

drivers/net/ethernet/microchip/lan743x_main.c:2944:25: warning:
 symbol 'lan743x_pm_ops' was not declared. Should it be static?
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NBryan Whitehead <Bryan.Whitehead@microchip.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>