i40e: remove unused function

After refactoring the client open and close code, this is no longer
needed. Remove it.

Change-ID: If8e6e32baa354d857c2fd8b2f19404f1786011c4
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>