bnx2x, bnx2fc: Use per port max exchange resources

The firmware supports a maximum of 4K FCoE exchanges. In 4-port devices,
or when working in multi-function mode, this resource needs to be distributed
between the various possible FCoE functions.

This information needs to be calculated by bnx2x and propagated into bnx2fc
via cnic. bnx2fc can then use this value to calculate corresponding xid
resources instead of using global constants.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>