If struct rmi_device_platform_data contains pointers to other struct,
it gets difficult to allocate a fixed size struct and copy it over between
drivers.

Change the pointers into a struct and change the code in rmi4 accordingly.
Reviewed-by: NAndrew Duggan <aduggan@synaptics.com>
Signed-off-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>