embestmx6boards: Fix CONFIG_CONSOLE_DEV

mars and riot boards use UART2 as console, so CONFIG_CONSOLE_DEV should point
to 'ttymxc1' instead.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Tested-by: Iain Paton <ipaton0@gmail.com>
1 file changed