rockchip: Enable Console MUX in ROCKPi N10

Enable Console multiplexing in ROCKPi N10 which would is
required to video out the console buffer.

Enable it.
Signed-off-by: NJagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang<kever.yang@rock-chips.com>

configs/rock-pi-n10-rk3399pro_defconfig

@@ -11,7 +11,6 @@ CONFIG_DEBUG_UART_CLOCK=24000000
 CONFIG_DEFAULT_DEVICE_TREE="rk3399pro-rock-pi-n10"
 CONFIG_DEBUG_UART=y
 # CONFIG_ANDROID_BOOT_IMAGE is not set
-# CONFIG_CONSOLE_MUX is not set
 CONFIG_DEFAULT_FDT_FILE="rockchip/rk3399pro-rock-pi-n10.dtb"
 CONFIG_MISC_INIT_R=y
 CONFIG_DISPLAY_BOARDINFO_LATE=y