drivers/aspeed/ast: Select `MAINBOARD_HAS_NATIVE_VGA_INIT`

Any board that uses the AST driver will have support for native graphics
init. So, select the option in the driver instead of every board.

Change-Id: I2bf42c168d1ffdda11857854889b74953abd7e40
Signed-off-by: Tristan Corrick <tristan@corrick.kiwi>
Reviewed-on: https://review.coreboot.org/c/30355
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/drivers/aspeed/ast2050/Kconfig

@@ -2,3 +2,4 @@ config DRIVERS_ASPEED_AST2050
 	bool
 	select DRIVERS_ASPEED_AST_COMMON
 	select HAVE_VGA_TEXT_FRAMEBUFFER
+	select MAINBOARD_HAS_NATIVE_VGA_INIT

src/mainboard/asus/kcma-d8/Kconfig

@@ -31,7 +31,6 @@ config BOARD_SPECIFIC_OPTIONS
 	select DRIVERS_I2C_W83795
 	select DRIVERS_ASPEED_AST2050
 	select MAINBOARD_FORCE_NATIVE_VGA_INIT
-	select MAINBOARD_HAS_NATIVE_VGA_INIT
 
 config MAINBOARD_DIR
 	string

src/mainboard/asus/kgpe-d16/Kconfig

@@ -32,7 +32,6 @@ config BOARD_SPECIFIC_OPTIONS
 	select DRIVERS_I2C_W83795
 	select DRIVERS_ASPEED_AST2050
 	select MAINBOARD_FORCE_NATIVE_VGA_INIT
-	select MAINBOARD_HAS_NATIVE_VGA_INIT
 
 config MAINBOARD_DIR
 	string