board: colibri_vf: fix compiling warning

This patch fixes the following compiler warning:
=============
board/toradex/colibri_vf/colibri_vf.c: In function 'ft_board_setup':
board/toradex/colibri_vf/colibri_vf.c:436:6: warning: unused variable 'ret' [-Wunused-variable]
=============

Fixes: be3f1a56bf8 ("video: fsl_dcu_fb: add DM_VIDEO support")
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
diff --git a/board/toradex/colibri_vf/colibri_vf.c b/board/toradex/colibri_vf/colibri_vf.c
index e9c5bc0..c09591e 100644
--- a/board/toradex/colibri_vf/colibri_vf.c
+++ b/board/toradex/colibri_vf/colibri_vf.c
@@ -433,7 +433,7 @@
 #if defined(CONFIG_OF_LIBFDT) && defined(CONFIG_OF_BOARD_SETUP)
 int ft_board_setup(void *blob, struct bd_info *bd)
 {
-#ifndef CONFIG_DM_VIDEO
+#if defined(CONFIG_VIDEO_FSL_DCU_FB) && !defined(CONFIG_DM_VIDEO)
 	int ret = 0;
 #endif
 #ifdef CONFIG_FDT_FIXUP_PARTITIONS