ARM: dts: aspeed: Add YADRO Nicole BMC

Nicole is an OpenPower machine with an Aspeed 2500 BMC SoC manufactured
by YADRO.

Signed-off-by: Alexander Filippov <a.filippov@yadro.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: Joel Stanley <joel@jms.id.au>