net: hns3: align return value type of atomic_read() with its output

Change output value type of atomic_read() from %u to %d.

Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>