i40e/i40evf: Use u64 values instead of casting them in TSO function

Instead of casing u32 values to u64 it makes more sense to just start out
with u64 values in the first place.  This way we don't need to create a
mess with all of the casts needed to populate a 64b value.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>