i40e: allocate memory safer

The sync_vsi_filter function was allocating memory in such
a way that it could sleep (GFP_KERNEL) which was causing a problem
when called by the team driver under rcu_read_lock(), which cannot
be held while sleeping.  Found with lockdep.

Change-ID: I4e59053cb5eedcf3d0ca151715be3dc42a94bdd5
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>