HNS3 supports setting rx-usecs|tx-usecs as 0, but it will not
update dynamically when adaptive-tx or adaptive-rx is enable.
This patch removes the Redundant check.

Fixes: a95e1f86 ("net: hns3: change the time interval of int_gl calculating")
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>