imx6: aristainetos: add DM_SERIAL support

add DM_SERIAL support for the aristainetos board, and
remove not used code from board code.

remove CONSOLE_OVERWRITE_ROUTINE.

Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/aristainetos2_defconfig b/configs/aristainetos2_defconfig
index 564c8c4..65702c0 100644
--- a/configs/aristainetos2_defconfig
+++ b/configs/aristainetos2_defconfig
@@ -2,6 +2,7 @@
 CONFIG_SYS_THUMB_BUILD=y
 CONFIG_ARCH_MX6=y
 CONFIG_SYS_TEXT_BASE=0x17800000
+CONFIG_SYS_MALLOC_F_LEN=0xe000
 CONFIG_TARGET_ARISTAINETOS2=y
 CONFIG_ENV_SIZE=0x3000
 CONFIG_ENV_OFFSET=0xD0000
@@ -12,7 +13,6 @@
 CONFIG_BOOTDELAY=3
 # CONFIG_CONSOLE_MUX is not set
 CONFIG_SYS_CONSOLE_IS_IN_ENV=y
-CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE=y
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_BOUNCE_BUFFER=y
 CONFIG_BOARD_TYPES=y
@@ -70,6 +70,7 @@
 CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_MII=y
 CONFIG_PWM_IMX=y
+CONFIG_DM_SERIAL=y
 CONFIG_SPI=y
 CONFIG_MXC_SPI=y
 CONFIG_USB=y