board: cm_fx6: Enable DM support for video, fix build error

Enable driver model for Video to remove the following
compile warning on CM-FX6 SOM based target:

===================== WARNING ======================
This board does not use CONFIG_DM_VIDEO Please update
the board to use CONFIG_DM_VIDEO before the v2019.07 release.
====================================================

This change introduced build error as shown:

LD      u-boot
drivers/built-in.o: In function ipu_displays_init'
arm-linux-ld.bfd: BFD (GNU Binutils) 2.29.1 assertion fail elf32-arm.c:9509
Makefile:1621: recipe for target 'u-boot' failed
make: *** [u-boot] Error 1

The DM converted video driver calls ipu_displays_init
in its probe, which inturn calls relevant board_video_skip.
Defining ipu_displays_init in the board file fixes build error.
Target was compile tested, build was clean.

Signed-off-by: Suniel Mahesh <sunil.m@techveda.org>

board/compulab/cm_fx6/cm_fx6.c

@@ -147,6 +147,11 @@ int board_video_skip(void)
 static inline void cm_fx6_setup_display(void) {}
 #endif /* CONFIG_VIDEO_IPUV3 */
 
+int ipu_displays_init(void)
+{
+	return board_video_skip();
+}
+
 #ifdef CONFIG_DWC_AHSATA
 static int cm_fx6_issd_gpios[] = {
 	/* The order of the GPIOs in the array is important! */

configs/cm_fx6_defconfig

@@ -90,4 +90,5 @@ CONFIG_USB_KEYBOARD=y
 CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE=y
 CONFIG_VIDEO_IPUV3=y
 CONFIG_VIDEO=y
+CONFIG_DM_VIDEO=y
 CONFIG_FDT_FIXUP_PARTITIONS=y