ice: Fix possible NULL pointer de-reference

A recent update to smatch is causing it to report the error "we previously
assumed 'm_entry->vsi_list_info' could be null". Fix that.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>