[ARM] enable arbitary speed tty ioctls and split input/output speed

Add the ioctls and values needed for this to the ARM26/ARM32 ports.  The
actual code has been in the base kernel for a while and automatically turns
on when a port sets the required defines.

[RMK: also added termbits.h changes to avoid build breakage]

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>