ARM: AM335x: add support for reading cpsw 2nd mac address from efuse

Adding support for reading cpsw 2nd mac address from efuse and pass it
to kernel via dtb which will be used in dual emac mode of cpsw.
Also adding mii command support to am335x common config.

Acked-by: Tom Rini <trini@ti.com>
Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>