video: make backlight and panel drivers optional

Not all boards use these drivers, so allow to disable them to fix
building boards with U-Boot binary image size restrictions.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index df7119d..1dbd09a 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -4,17 +4,18 @@
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
 ifdef CONFIG_DM
+obj-$(CONFIG_BACKLIGHT) += backlight-uclass.o
 obj-$(CONFIG_BACKLIGHT_GPIO) += backlight_gpio.o
 obj-$(CONFIG_BACKLIGHT_PWM) += pwm_backlight.o
 obj-$(CONFIG_CONSOLE_NORMAL) += console_normal.o
 obj-$(CONFIG_CONSOLE_ROTATION) += console_rotate.o
 obj-$(CONFIG_CONSOLE_TRUETYPE) += console_truetype.o fonts/
 obj-$(CONFIG_DISPLAY) += display-uclass.o
-obj-$(CONFIG_DM_VIDEO) += backlight-uclass.o
 obj-$(CONFIG_VIDEO_MIPI_DSI) += dsi-host-uclass.o
-obj-$(CONFIG_DM_VIDEO) += panel-uclass.o simple_panel.o
 obj-$(CONFIG_DM_VIDEO) += video-uclass.o vidconsole-uclass.o
 obj-$(CONFIG_DM_VIDEO) += video_bmp.o
+obj-$(CONFIG_PANEL) += panel-uclass.o
+obj-$(CONFIG_SIMPLE_PANEL) += simple_panel.o
 endif
 
 obj-${CONFIG_EXYNOS_FB} += exynos/