Bluetooth: Update management interface revision

For each kernel release where commands or events are added to the
management interface, the revision field should be increment by one.

The increment should only happen once per kernel release and not
for every command/event that gets added. The revision value is for
informational purposes only, but this simple policy would make any
future debugging a lot simple.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>