ARM: dts: aspeed: amd-ethanolx: Enable KCS channel 3

The KCS interface on the LPC channel 3 in the controller
is used for the in-band BMC<->BIOS IPMI communication.
0xCA2 is a default host CPU LPC IO address for this
interface.

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
Reviewed-by: Supreeth Venkatesh <supreeth.venkatesh@amd.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20201027123722.2935-2-aladyshev22@gmail.com


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