i40e: Check and correct speed values for link on open

If our card has been put in an unstable state due to
other drivers interacting with it, speed settings
might be incorrect. If incorrect, forcefully reset them
on open to known default values.

Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>