boards: st: stm32f4_disco: add support for audio output

The stm32f4_disco board features an audio codec (cs43l22) connected to
an audio jack (TRS) output, and to the stm32f4 via I2S and I2C. To set
this up, several peripherals must be configured:

- Enable I2S3 and the PLLI2S (tuned for 22.05/44.1/88.2 kHz audio)
- Enable DMA1 (used by I2S3)
- Enable I2C1, and add definition for the CS43L22 on the bus
- Disable USART1 and CAN1 which have conflicting pinctrl with I2C1

This new setting is more appropriate, because this gives access to the
audio jack output by default (instead of "bare" pins not connected to
anything on the board).

Signed-off-by: Titouan Christophe <moiandme@gmail.com>