docs: aspeed: Add new boards

Add X11, FP5280G2, G220A, Rainier and Fuji. Mention that Swift will be
removed in v7.0.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-id: 20211117065752.330632-2-joel@jms.id.au
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
1 file changed