bnx2x: ethtool -d might cause timeout in log

This changes slightly the set of registers read during `ethtool -d'.
Without this change, it's possible the HW will generate a grc Attention which
will be logged into system logs as `grc timeout'.

Signed-off-by: Dmitry Kravkov <Dmitry.Kravkov@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>