ARM: dts: aspeed: Add Inspur NF5280M6 BMC machine

The Inspur NF5280M6 is an x86 platform server with an AST2500-based BMC.
This dts file provides a basic configuration for its OpenBMC
development.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Signed-off-by: Ping Guo <guoping@inspur.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210526092206.22760-1-guopingjn@gmail.com


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