ARM: dts: aspeed: wedge400: Use common flash layout

Simplify wedge400 flash layout by using the common layout defined in
"facebook-bmc-flash-layout-128.dtsi".

Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210805222818.8391-3-rentao.bupt@gmail.com


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