video: move MXS to Kconfig

Move CONFIG_VIDEO_MXS from board headers to Kconfig
and drop it from obsolete cfb_console driver.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/configs/colibri_imx7_defconfig b/configs/colibri_imx7_defconfig
index 88d6994..6713904 100644
--- a/configs/colibri_imx7_defconfig
+++ b/configs/colibri_imx7_defconfig
@@ -91,6 +91,7 @@
 CONFIG_CI_UDC=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_DM_VIDEO=y
+CONFIG_VIDEO_MXS=y
 CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_SPLASH_SCREEN=y
 CONFIG_SPLASH_SCREEN_ALIGN=y