i40evf: request reset on tx hang

If the kernel watchdog bites us, ask the PF to reset us and attempt to
reinit the driver.

Change-ID: Ic97665aeeed71ce712b9c4f057e78ff8372522b9
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>