Enable the 2 ethernet ports as CPSW ports in dual-mac mode

Signed-off-by: Roger Quadros <rogerq@ti.com>
[nsekhar@ti.com: use AM33XX_IOPAD()]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>