tg3: Dump registers when status block shows errors

This patch monitors the error bit of the status word within the status
block.  If it is set, the driver will dump the driver state after
validating the error and then reset the chip.

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