i40e: Give link more time after setting flow control

Give link a little more time to come back up after setting flow control
before resetting. In the new NVMs it is taking longer for link to come back.
This causes the driver to attempt to reset the link, which then errors
because the firmware was already in the middle of a reset. Also, initialize
err to 0.

Change-ID: I1cc987a944e389d8909c262da5796f50722b4d6b
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Jim Young <jmyoungx@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>