Each PCTYPE can only have one specific FDIR input set at one time.
Add input set requirement info to i40e doc.
Bugzilla ID: 403
Fixes: 14c66a451ef7 ("net/i40e: flush tunnel filters")
Cc: stable@dpdk.org
Signed-off-by: Wei Zhao <wei.zhao1@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>