v850: enable arbitary speed tty ioctls

Adding the defines/macros activates the existing code in the tty layer
and allows this platform to use the arbitary speed ioctl setting layer

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>