[TG3]: PCI command adjustment

This patch changes the way the driver works with the PCI command
register.  It adjusts the access size from dwords to words.  This patch
is done both as a PCI configuration space cleanup and as preparatory
work for PCI error recovery.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>