drm/exynos: fixed build dependency for DRM_EXYNOS_FIMD

FB based FIMD and DRM based FIMD drivers use same hardware
so with this patch, only one of them would be selected.
Signed-off-by: NInki Dae <inki.dae@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/Kconfig

@@ -13,7 +13,7 @@ config DRM_EXYNOS
 
 config DRM_EXYNOS_FIMD
 	tristate "Exynos DRM FIMD"
-	depends on DRM_EXYNOS
+	depends on DRM_EXYNOS && !FB_S3C
 	default n
 	help
 	  Choose this option if you want to use Exynos FIMD for DRM.