iavf: Check for duplicate TC flower filter before parsing

Record of all the TC flower filters are kept for local book keeping, so
take advantage of that and check for duplicate filter even before sending
a request to the PF driver.

Signed-off-by: Avinash Dayanand <avinash.dayanand@intel.com>
Signed-off-by: Jun Zhang <xuejun.zhang@intel.com>
Tested-by: Bharathi Sreenivas <bharathi.sreenivas@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>