[PATCH] tg3: add 5714/5715 support

Add complete support for 5714/5715. These chips are very similar to
5780 so the changes are very trivial. A TG3_FLG2_5780_CLASS flag is
added to identify these chips.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>