Make the vexpress-a9 board alias the first NOR flash region at
address zero, like vexpress-a15. This makes "-bios" actually usable
on this board.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1404310070-3561-1-git-send-email-peter.maydell@linaro.org
Reviewed-by: Greg Bellows <greg.bellows@linaro.org>