Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Resurrect the sbni(4) driver. Someone finally tested the MPSAFE patches and
the driver worked ok with them.

Tested by: friends of yar

Make sbni(4) MPSAFE:
- Add a mutex to the softc and use it to protect the softc and device
hardware.
- Setup interrupt handler after attaching device to network stack.
- Use device_set_desc() rather than device_quiet() plus a manual printf
that simulates the normal probe printf.
- Axe next_sbni_unit and instead just leave room for two sbni devices for
each bus attachment.
- Don't bzero the already-zero'd softc.
- Add a detach method to the PCI driver.
- Add a lock to protect the list of available devices used to chain
interrupt handlers for dual port ISA cards.
- Remove unused watchdog routine.
- If if_alloc() fails, make sbni_attach() return an error rather than
panic'ing.
- Consolidate code to free bus resources into sbni_release_resources().
- Clear IFF_DRV_RUNNING|OACTIVE in stop() routine instead of in callers.
- Let ether_ioctl() handle SIOCSIFMTU.

Stop embedding struct ifnet at the top of driver softcs. Instead the
struct ifnet or the layer 2 common structure it was embedded in have
been replaced with a struct ifnet pointer to be filled by a call to the
new function, if_alloc(). The layer 2 common structure is also allocated
via if_alloc() based on the interface type. It is hung off the new
struct ifnet member, if_l2com.

This change removes the size of these structures from the kernel ABI and
will allow us to better manage them as interfaces come and go.

Other changes of note:
- Struct arpcom is no longer referenced in normal interface code.
Instead the Ethernet address is accessed via the IFP2ENADDR() macro.
To enforce this ac_enaddr has been renamed to _ac_enaddr.
- The second argument to ether_ifattach is now always the mac address
from driver private storage rather than sometimes being ac_enaddr.

Reviewed by: sobomax, sam

Start each of the license/copyright comments with /*-, minor shuffle of lines

Make driver portable:
- bus_space'ify
- generate fake ethernet address using read_random() instead of reading
from timer i/o ports

Other minor fixes:
- remove "hack" in connect_to_master()
- use M_ZERO
- remove unused variable in sbni_ioctl()
- properly release irq in sbni_attach_isa() on attach errors

Rename a variable that might accidentally be duplicated elsewhere.

Add driver for Granch SBNI12-xx ISA and PCI network adapters.

MFC after: 1 week