8xxx: Second UART port added for MPC85xx, MPC83xx, MPC86xx processors

Defining the next two configs allows to switch the serial port from the
console using the setenv stdin and stdout
  1. #define CONFIG_SERIAL_MULTI 1 /* Enable both serial ports */
  2. #define CONFIG_SYS_CONSOLE_IS_IN_ENV /* determine from environment */

Signed-off-by: Poonam Aggrwal <poonam.aggrwal@freescale.com>
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>