i40e: setup flow director only if enabled

i40e: setup flow director only if enabled

In order not to affect the FVL's performance by default setting, this
patch moves the flow director initialization from i40e_pf_setup to
i40e_dev_configure according to the mode in fdir configure info.
Then the resources used for flow director will be only setup if it is enabled.

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>