staging: line6: changed interface of line6_pod_transmit_parameter()

Adjusted interface of line6_pod_transmit_parameter() to take changes of
line6_transmit_parameter() into account

Signed-off-by: Johannes Thumshirn <morbidrsa@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>