net: hns3: add reset checking before set channels

hns3_set_channels() should check the resetting status firstly,
since the device will reinitialize when resetting. If the
reset has not completed, the hns3_set_channels() may access
invalid memory.

Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>