dm: arm: imx: cx9020: migrate to dm_video

Enable DM_VIDEO in config and don't overwrite console so it can be set
from environment

Acked-by: Patrick Bruenn <p.bruenn@beckhoff.com>
Signed-off-by: Steffen Dirkwinkel <s.dirkwinkel@beckhoff.com>
diff --git a/board/beckhoff/mx53cx9020/Makefile b/board/beckhoff/mx53cx9020/Makefile
index 423a553..7f15fc5 100644
--- a/board/beckhoff/mx53cx9020/Makefile
+++ b/board/beckhoff/mx53cx9020/Makefile
@@ -4,4 +4,4 @@
 # Patrick Bruenn <p.bruenn@beckhoff.com>
 
 obj-y               += mx53cx9020.o
-obj-$(CONFIG_VIDEO) += mx53cx9020_video.o
+obj-$(CONFIG_DM_VIDEO) += mx53cx9020_video.o