Track the base absolute ID of ingress and egress queues.

Use this to map an absolute queue ID to a logical queue ID in interrupt
handlers. For the regular cxgbe/cxl drivers this should be a no-op as
the base absolute ID should be zero. VF devices have a non-zero base
absolute ID and require this change. While here, export the absolute ID
of egress queues via a sysctl.

Reviewed by: np
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D7446