bnxt_en: Improve VF resource accounting.

We need to keep track of all resources, such as rx rings, tx rings,
cmpl rings, rss contexts, stats contexts, vnics, after we have
divided them for the VFs.  Otherwise, subsequent ring changes on
the PF may not work correctly.

We adjust all max resources in struct bnxt_pf_info after they have been
assigned to the VFs.  There is no need to keep the separate
max_pf_tx_rings and max_pf_rx_rings.

When SR-IOV is disabled, we call bnxt_hwrm_func_qcaps() to restore the
max resources for the PF.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>