drivers/i2s/ i2s_ll_stm32.c: Fix wrong DMA burst length value
drivers/i2s/ i2s_ll_stm32.c: Fix wrong DMA burst length value

'0' is not a valid value for DMA burst length. Set it to '1'
to perform a SINGLE transfer.

Signed-off-by: Armando Visconti <d93ca24ded08d03c3aa60af6d2fd0eb7ce54da11@st.com>

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