ARM: dts: aspeed: yamp: Set 32MB FMC flash layout

Set 32MB FMC flash layout in Yamp device tree explicitly because flash
layout settings were removed from "ast2500-facebook-netbmc-common.dtsi".

Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Link: https://lore.kernel.org/r/20200824211948.12852-4-rentao.bupt@gmail.com


Signed-off-by: Joel Stanley <joel@jms.id.au>