staging: most: change signature of function probe_channel

This patch adds the param argument to the function parameter of
the call-back probe_channel. This parameter is needed to configure
the channels of an attached device.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>