lib/edid.c: Allow use of when not NGI

Change-Id: I8709e3e61686979137b08d24efad903700d18e0b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/19501
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/device/Kconfig

@@ -24,6 +24,7 @@ config MAINBOARD_HAS_NATIVE_VGA_INIT
 # FIXME Ugly hack to allow Z9s driver native framebuffer configuration
 config NATIVE_VGA_INIT_USE_EDID
 	bool
+	depends on MAINBOARD_DO_NATIVE_VGA_INIT
 	default n if DRIVERS_XGI_Z9S || MAINBOARD_USE_LIBGFXINIT
 	default y if !DRIVERS_XGI_Z9S