i40e: count allocation errors

Driver already counted allocation errors, so print
them as part of the ethtool -S output.  Useful for debugging
if your system is having trouble making memory available for
the driver.

Change-ID: I83839fa86e81e6d80f03b917c88dd3ef9a64dde0
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>