hw/char/stm32l4x5_usart: Add options for serial parameters setting Add a function to change the settings of the serial connection. Signed-off-by: Arnaud Minier <arnaud.minier@telecom-paris.fr> Signed-off-by: Inès Varhol <ines.varhol@telecom-paris.fr> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 20240329174402.60382-4-arnaud.minier@telecom-paris.fr Signed-off-by: Peter Maydell <peter.maydell@linaro.org>