video: Migrate exynos display options to Kconfig

Following how it's done for the majority of drivers, add a new
VIDEO_EXYNOS option and Kconfig file under drivers/video/exynos and list
the current options there.

Cc: Anatolij Gustschin <agust@denx.de>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 965b587..4ecc158 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -583,6 +583,8 @@
 
 source "drivers/video/ti/Kconfig"
 
+source "drivers/video/exynos/Kconfig"
+
 config LOGICORE_DP_TX
 	bool "Enable Logicore DP TX driver"
 	depends on DISPLAY