i40e: Rewrite Flow Director busy wait loop

We can reorder the busy wait loop at the start of the Flow Director
transmit function to reduce the overall code size while still retaining the
same functionality.  As such I am taking advantage of the opportunity to do
so.

Change-ID: I34c403ca001953c6ac9816e65d5305e73d869026
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>