net: hns3: cleanup some coding style issue

This patch removes some unnecessary return value assignments,
some duplicated printing in the caller, refines the judgment
of 0 and uses le16_to_cpu to replace __le16_to_cpu.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>