ARM: dts: aspeed: ast2400: Add video engine support

Add a node to describe the video engine on AST2400.

These changes were copied from aspeed-g5.dtsi

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