imx: mx6ul_14x14_evk: fix link issue

Since recent splash changes common code for splashscreen logo
should be used instead of adding duplicated code under board
directories. mx6ul_9x9_evk and mx6ul_14x14_evk configurations
used old board specific logo code and do not link, fix them.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/mx6ul_9x9_evk_defconfig b/configs/mx6ul_9x9_evk_defconfig
index 81f9b5b..0b3b2b1 100644
--- a/configs/mx6ul_9x9_evk_defconfig
+++ b/configs/mx6ul_9x9_evk_defconfig
@@ -71,3 +71,4 @@
 CONFIG_DM_USB=y
 CONFIG_USB_STORAGE=y
 CONFIG_DM_VIDEO=y
+CONFIG_SYS_WHITE_ON_BLACK=y