tg3: Remove define and single use of GET_CHIP_REV_ID

It's the same value as tp->pci_chip_rev_id so use that
instead.  This makes all CHIPREV_ID_<foo> tests the same.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>