staging: fbtft: ili9341: use macro FBTFT_REGISTER_SPI_DRIVER

Using FBTFT_REGISTER_DRIVER resolves to a NULL struct spi_device_id. This
ultimately causes a warning when the module probes. Fixes it.

Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Link: https://lore.kernel.org/r/20230718172024.67488-1-rgallaispou@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>