ethdev: unification of flow types

ethdev: unification of flow types

Flow types was defined actually for i40e hardware specifically,
and wasn't able to be used for defining RSS offload types of all
PMDs. It removed the enum flow types, and uses macros instead
with new names. The new macros can be used for defining RSS
offload types later. Also modifications are made in i40e and
testpmd accordingly.

Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Acked-by: Jingjing Wu <jingjing.wu@intel.com>
[Thomas: merge with new flow director API]
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>