drivers: pinmux: stm32: add pin for I2S3_WS on F4 series
drivers: pinmux: stm32: add pin for I2S3_WS on F4 series

Enable I2S3 WS functionality on PA15 pin

Signed-off-by: Abe Kohandel <c9a2a5540dcfc3ebad99e723223675d3f15edc54@electronshepherds.com>

nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,nashif/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,nashif/zephyr