Input: pxspad - fix unused data warning when force feedback not enabled

The functions using this data were protected with #ifdef
CONFIG_JOYSTICK_PSXPAD_SPI_FF. Do the same for the data used only in
those functions.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20221204180841.2211588-33-jic23@kernel.org


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>