RDMA/bnxt_re: Enable SRIOV VF support on Broadcom's 57500 adapter series

Broadcom's 575xx adapter series has support for SRIOV VFs.  Making changes
to enable SRIOV VF support. There are two major area where changes are
done:

 - Added new DB location for control-path and data-path DB ring

 - New devices do not need to issue the sriov-config slow-path command
   thus, skipping to call that firmware command.

For now enabling support for 64 RoCE VFs.

Link: https://lore.kernel.org/r/1570081715-14301-1-git-send-email-devesh.sharma@broadcom.com


Signed-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>