ARM: dts: aspeed: ast2600-evb: Enable video engine

Enable video engine and reserve memory for it.

Signed-off-by: Howard Chiu <howard_chiu@aspeedtech.com>
Link: https://lore.kernel.org/r/SG2PR06MB23159B914BF7EF937FEDD2B5E61E9@SG2PR06MB2315.apcprd06.prod.outlook.com


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