e1000e: move settting of flow control refresh timer to link setup code

The flow control refresh timer value needs to be saved off so that it can
be programmed into the approrpiate register when applicable but without a
reset, e.g. when changing flow control parameters via ethtool.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>