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

This boot log warnings during PHY detection.
Signed-off-by: NYogesh Siraswar <yogeshs@ti.com>
Signed-off-by: NAndrew F. Davis <afd@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>