Convert CONFIG_VIDEO to Kconfig

This converts the following to Kconfig:
   CONFIG_VIDEO

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/configs/socrates_defconfig b/configs/socrates_defconfig
index 75db38f..52f67c3 100644
--- a/configs/socrates_defconfig
+++ b/configs/socrates_defconfig
@@ -1,4 +1,5 @@
 CONFIG_PPC=y
+CONFIG_VIDEO=y
 CONFIG_MPC85xx=y
 CONFIG_TARGET_SOCRATES=y
 CONFIG_FIT=y