boards: arm: st: nucleo_h7s3l8: Add fdcan1

Enable support for FDCAN1 on nucleo_h7s3l8 board. PD0 (RX) and PD1 (TX)
are used for interfacing an external CAN transceiver according to the
breakout connector description in the board's schematic.

Signed-off-by: Thomas Decker <decker@jb-lighting.de>