configs: stm32mp25: Enable MFD timer and PWM for stm32mp25_defconfig

configs: stm32mp25: Enable MFD timer and PWM for stm32mp25_defconfig

Enable the following configs:

- CONFIG_MFD_STM32_TIMERS: enables support for the STM32 multifunction
                           timer
- CONFIG_DM_PWM: enables support for pulse-width modulation devices
- CONFIG_CMD_PWM: enables 'pwm' command to control PWM channels
- CONFIG_PWM_STM32: enables support for the STM32 PWM devices

Signed-off-by: Cheick Traore <cheick.traore@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>