ARM: dts: aspeed: mihawk: IO expander uses TCA9554 driver

Set smbus_en of IO expander to 1 in order to be able to read sensor.

Signed-off-by: Ben Pai <Ben_Pai@wistron.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>