boards: stm32f412g_disco: Add arduino headers

Added arduino gpios, and the typically used aliases for
arduino_spi, arduino serial and arduino_i2c

Signed-off-by: Kim Bøndergaard <kim.boendergaard@escoglobal.com>
Signed-off-by: Kim Bøndergaard <kim@fam-boendergaard.dk>
3 files changed