usb/ipheth: Add iPhone 5 support

I noticed that the iPhone ethernet driver did not support
iPhone 5. I quickly added support to it in my kernel, here's
a patch.

Signed-off-by: Jay Purohit <jspurohit@velocitylimitless.com>
Acked-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Jan Ceuleers <jan.ceuleers@computer.org>
Signed-off-by: David S. Miller <davem@davemloft.net>