Passing 'novga' only adds '-vga none' to the qemu commandline and does
not prevent other vga devices from being added, contrary to the
documentation/help. Clean-up the vga logic and add the ability to
prevent other vga devices from being added.
Signed-off-by: Jon Mason <jon.mason@arm.com>
Change-Id: I7ff8f9f3e419ce8bae3f3847d75f9275ca30406a Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
