ARM: dts: am43xx-epos-evm: Remove extra CPSW EMAC entry

On am438x EPOS boards there is only one ethernet port, remove extra
port definition.

This boot log warnings during PHY detection.

Signed-off-by: Yogesh Siraswar <yogeshs@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>