external_access: Increase the terminal timeout

Signed-off-by: Alistair Francis <alistair23@gmail.com>
netduinoplus2: Update the way the SYSCFG device is connected

Signed-off-by: Alistair Francis <alistair23@gmail.com>
netduinoplus2: Reduce the size of the peripheral memory

Signed-off-by: Alistair Francis <alistair23@gmail.com>