igb: Fix stats output on i210/i211 parts.

Due to a hardware issue, on i210 and i211 parts, the TNCRS statistic
provides an invalid value.  This patch changes the update stats function
to increment the stat only for non-i210/i211 parts.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>