i40e: factor out queue control from i40e_vsi_control_(tx|rx)

A future patch will need to be able to handle controlling queues without
waiting until all VSIs are handled. Factor out the direct queue
modification so that we can easily re-use this code. The result is also
a bit easier to read since we don't embed multiple single-letter loop
counters.

Change-ID: Id923cbfa43127b1c24d8ed4f809b1012c736d9ac
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>