nimble/ll: Fix SyncInfo units when no offset is provided

If periodic advertising event is too far in future to be represented
in SyncInfo, offset is set to 0 and units should also not be set.

nimble/controller/src/ble_ll_adv.c

@@ -634,6 +634,7 @@ ble_ll_adv_put_syncinfo(struct ble_ll_adv_sm *advsm,
                 units |= 0x40;
             } else {
                 offset = 0;
+                units = 0x00;
             }
         }