RDMA/i40iw: Fix for the size of kernel mode SQ

Fix to calculate the SQ size based on the max
frag_count, requested by the application instead
of overwriting it with the max supported frag_count

Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>