tg3: Use pci_dev pm_cap

Use the already existing pm_cap variable in struct pci_dev for
determining the power management offset.  This saves the driver from
having to keep track of an extra variable.

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Cc: Nithin Nayak Sujir <nsujir@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.h

@@ -3234,7 +3234,6 @@ struct tg3 {
 	u8				pci_lat_timer;
 
 	int				pci_fn;
-	int				pm_cap;
 	int				msi_cap;
 	int				pcix_cap;
 	int				pcie_readrq;