ARM: dts: k2g-evm: Enable UART 2

66AK2G GP EVM has a Baseboard Management Controller (BMC) on board.
This controller handles things like setting the SoCs boot mode along
with controlling the on board character LCD display module.

Enable UART2 which communicates with the BMC. This enables userspace
applications to display something on the onboard LCD controlled by the
BMC.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>