Char: rocket, fix dynamic_dev tty

- register_device unconditionally (non-pci dependent) to have also isa
  devices in /dev
- unregister devices on module removal
- don't set TTY_DRIVER_DYNAMIC_DEV twice (removed the one dependent on some
  macro)

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Ferenc Wagner <wferi@niif.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>