ice: move VSI delete outside deconfig

In deconfig VSI shouldn't be deleted from hw.

Rewrite VSI delete function to reflect that sometimes it is only needed
to remove VSI from hw without freeing the memory:
ice_vsi_delete() -> delete from HW and free memory
ice_vsi_delete_from_hw() -> delete only from HW

Value returned from ice_vsi_free() is never used. Change return type to
void.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>