net/hns3: report speed capability for PF

The speed capability of the device can be reported to the upper-layer app
in rte_eth_dev_info_get API. In this API, the speed capability is derived
from the 'supported_speed', which is the speed capability actually
supported by the NIC. The value of the 'supported_speed' is obtained
once in the probe stage and may be updated in the scheduled task to deal
with the change of the transmission interface.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Signed-off-by: Min Hu (Connor) <humin29@huawei.com>