libgfxinit: Select CONFIG_VGA when needed

This wasn't caught earlier because many boards select it manually.

Change-Id: I245ef8f44923b5384123bd549570db7c348e03b8
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/18771
Tested-by: build bot (Jenkins)
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

src/device/Kconfig

@@ -55,6 +55,7 @@ config MAINBOARD_USE_LIBGFXINIT
 	depends on MAINBOARD_HAS_LIBGFXINIT
 	select MAINBOARD_HAS_NATIVE_VGA_INIT_TEXTMODECFG
 	select RAMSTAGE_LIBHWBASE
+	select VGA if !FRAMEBUFFER_KEEP_VESA_MODE
 	default n
 	help
 	  Use the SPARK library `libgfxinit` for the native graphics