ARM: dts: aspeed-ast2500: Add I2C devices

Enable the buses that are in use and the devices that are attached.
Currently that includes temperature measurement and EEPROM.

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>