common/iavf: add GRE header type
common/iavf: add GRE header type

Add a virtchnl protocol header type to support AVF FDIR and RSS for GRE.

Signed-off-by: Wenjun Wu <f2c8f8c385402f4722593bcff277b2cd6b66f35b@intel.com>
Acked-by: Qi Zhang <9e9e58ffa71a29bb7b87766b362515be648fcbe0@intel.com>

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