spi: spidev: add two new spi mode bits

Allow userspace to set SPI_MOSI_IDLE_LOW and the SPI_3WIRE_HIZ mode bit
using the SPI_IOC_WR_MODE32 ioctl.

Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com>
Link: https://lore.kernel.org/r/20230530141641.1155691-4-boerge.struempfel@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>