Staging: ipack/devices/ipoctal: remove superfluous function.

ipoctal_write_tty and ipoctal_write are merged.

Signed-off-by: Jens Taprogge <jens.taprogge@taprogge.org>
Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>