sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

ntb: Remove unused devclass arguments to DRIVER_MODULE.

Report NTB link speed to console and interface.

MFC after: 2 weeks

Once more refactor KPI between ntb_transport(4) and if_ntb(4)..

New design allows to attach multiple consumers to ntb_transport(4) instance.
Previous design obtained from Linux theoretically allowed that, but was not
practically usable (Linux also has only one consumer driver now).

NewBus'ify NTB subsystem.

This follows NTB subsystem modularization in Linux, tuning it to FreeBSD
native NewBus interfaces. This change allows to support different types
of hardware with different drivers, support multiple NTB instances in a
system, ntb_transport module use for needs other then if_ntb, etc.

Sponsored by: iXsystems, Inc.