drivers: spi: spi_ll_stm32: Fix uncleared MODF flag

Clear raised MODF flag, if not done the flag stay set forever.

Fixes https://github.com/zephyrproject-rtos/zephyr/issues/17363

Signed-off-by: Yaël Boutreux <yael.boutreux@st.com>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
1 file changed