imx: convert mx51evk board to DM_VIDEO

Migration to DM_VIDEO driver is long overdue. Update defconfig
to enable usage of converted ipuv3 driver DM configuration.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/configs/mx51evk_defconfig b/configs/mx51evk_defconfig
index dbc4d85..5dfa3be 100644
--- a/configs/mx51evk_defconfig
+++ b/configs/mx51evk_defconfig
@@ -36,7 +36,13 @@
 CONFIG_USB_HOST_ETHER=y
 CONFIG_USB_ETHER_ASIX=y
 CONFIG_USB_ETHER_SMSC95XX=y
+CONFIG_DM_VIDEO=y
 CONFIG_VIDEO_IPUV3=y
-CONFIG_VIDEO=y
-# CONFIG_VIDEO_SW_CURSOR is not set
+# CONFIG_BACKLIGHT is not set
+# CONFIG_CMD_VIDCONSOLE is not set
+# CONFIG_VIDEO_BPP8 is not set
+# CONFIG_VIDEO_BPP32 is not set
+# CONFIG_VIDEO_ANSI is not set
+# CONFIG_PANEL is not set
+CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_OF_LIBFDT=y