spi: spi-fsl-lpspi: make struct lpspi_config::mode u32

spi: spi-fsl-lpspi: make struct lpspi_config::mode u32

The struct lpspi_config::mode holds a copy of the mode of struct
spi_device::mode. In commit 937e6d756422 ("spi: expand mode support") the
struct spi_device::mode was increased from u16 to u32.

Increase the struct lpspi_config::mode to u32 avoid truncating the mode
variable.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://patch.msgid.link/20260319-spi-fsl-lpspi-cleanups-v2-11-02b56c5d44a8@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>