i40iw: Do not generate CQE for RTR on QP flush

If RTR WQE is posted and QP is flushed, a CQE is
incorrectly generated for the RTR WQE. Add code
to look for the RTR and not generate a CQE when
QP is flushed.

Fixes: 280cfc4b ("i40iw: user kernel shared files")
Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>