net: hns3: Refine the MSIX allocation for PF

The offset of msix number for roce is different between different
revision id. We should get it from firmware, instead of a fix value.
This patch refines the msix allocation, make it compatible.

Signed-off-by: Jian Shen <shenjian15@huawei.com>
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>