Intel Edison has three UART ports, i.e.
port 0 - Bluetooth
port 1 - auxiliary, available for general purpose use
port 2 - debugging, usually console output is here
Enable all of them for future use.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>