ixgbe: Remove CS4227 diagnostic code

Testing has now shown that the diagnostic code used with the CS4227
is no longer needed, so remove it.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Darin Miller <darin.j.miller@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>