i40e: Fix sparse warning: missing error code 'err'

Set proper return values inside error checking if-statements.

Previously following warning was produced when compiling against sparse.
i40e_main.c:15162 i40e_init_recovery_mode() warn: missing error code 'err'

Fixes: 4ff0ee1a ("i40e: Introduce recovery mode support")
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>