e1000: two workarounds were incomplete, fix them

1) 82544 does not need last_tx_tso workaround, it interferes with the 82544
workaround too
2) 82544 hang workaround was using the address of the page struct instead of
the physical address as its "workaround decider" not sure how that ever worked

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>