net: hns3: add DFX registers information for ethtool -d

Now we can use ethtool -d command to dump some registers. However,
these registers information is not enough to find out where the problem is.

This patch adds DFX registers information after original registers
when use ethtool -d commmand to dump registers. Also, using macro
replaces some related magic number.

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Reviewed-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>