Input: synaptics-rmi4 - remove the exporting of rmi_2d_sensor_set_input_params

The function rmi_2d_sensor_set_input_params is declared static and marked
EXPORT_SYMBOL_GPL, which is at best an odd combination. Because the
function is not used outside of the drivers/input/rmi4/rmi_2d_sensor.c
file it is defined in, this commit removes the EXPORT_SYMBOL_GPL() marking.

Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>