i40e: Refine an error message to avoid confusion

Change a warning message to indicate what may have really happened when
the init_shared_code call fails.

Change-ID: I616ace40fed120d0dec86dfc91ab2d7cde466904
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>