ixgbe: avoid enabling interrupt with zero vector
ixgbe: avoid enabling interrupt with zero vector

Signed-off-by: Cunming Liang <7edc6dd0948177c688da9b288939d80da3db4303@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk