e1000e: unexpected "Reset adapter" message when cable pulled

When there is heavy traffic and the cable is pulled, the driver must reset
the adapter to flush the Tx queue in hardware.  This causes the reset path
to be scheduled and logs the message "Reset adapter" which could be mis-
interpreted as an error by the user.  Change how the reset path is invoked
for this scenario by using the same method done in an existing work-around
for 80003es2lan (i.e. set a flag and if the flag is set in the reset code
do not log the "Reset adapter" message since the reset is expected).

Re-name the FLAG_RX_RESTART_NOW to FLAG_RESTART_NOW since it is used for
resets in both the Rx and Tx specific code.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>