drivers: spi: spi_ll_stm32: Fix the master mode not work.

On the STM32MP1 and STM32H7 Series SoC, if slave select pin control by
software on master mode operation, the SS input/output polarity (SSIOP)
should be set to high level avoid the mode fault (MODF) error.

Signed-off-by: Harry Jiang <explora26@gmail.com>
1 file changed