mainboard/asus/kfsn4-dre: Enable VGA support

The ASUS KFSN4-DRE has full native VGA support, enable support for the
VGA device by default in the Kconfig file.

Change-Id: I09fc8845a30f26ca49f3547812f9784621ff4b5e
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/10673
Tested-by: build bot (Jenkins)
Reviewed-by: Francis Rowe <info@gluglug.org.uk>
Reviewed-by: Martin Roth <gaumless@gmail.com>

src/mainboard/asus/kfsn4-dre/Kconfig

@@ -21,6 +21,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select MMCONF_SUPPORT_DEFAULT
 	select DRIVERS_I2C_W83793
 	select DRIVERS_XGI_Z9S
+	select VGA
 	select MAINBOARD_HAS_NATIVE_VGA_INIT
 	select MAINBOARD_HAS_NATIVE_VGA_INIT_TEXTMODECFG