net: hns3: Enable HW GRO for Rev B(=0x21) HNS3 hardware

HNS3 hardware Revision B(=0x21) supports Hardware GRO feature. This
patch enables this feature in the HNS3 PF/VF driver.

Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>