ixgbe: add ECC warning for legacy interrupts

Noticed that the legacy Interrupt handler didn't have the same
ECC warning as did the MSI.  So this patch adds it.

Signed-off-by: Don Skidmore <donald.c.skidmore>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>