e1000: add queue restart counter

Add a netif_wake/start_queue counter to the ethtool statistics to indicated
to the user that their transmit ring could be too small for their workload.

Signed-off-by: Jesse brandeburg <jesse.brandeburg@intel.com>
Cc: Jamal Hadi <hadi@cyberus.ca>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>