device: avoid uninit var warning

cppcheck:

src/util-device.c:455:17: error: Uninitialized variables: *ndev.dev, *ndev.tenant_id_set, *ndev.id, *ndev.next, *ndev.tenant_id, *ndev.offload_orig [uninitvar]
        *ldev = *ndev;
                ^
src/util-device.c:618:36: note: Calling function 'LiveDeviceForEach', 2nd argument '&ndev' value is <Uninit>
    while(LiveDeviceForEach(&ldev, &ndev)) {
                                   ^
src/util-device.c:455:17: note: Uninitialized variables: *ndev.dev, *ndev.tenant_id_set, *ndev.id, *ndev.next, *ndev.tenant_id, *ndev.offload_orig
        *ldev = *ndev;
                ^

Bug: #5291.
(cherry picked from commit 3bc50df9c3)

src/util-device.c

@@ -611,7 +611,7 @@ void LiveDevAddBypassSuccess(LiveDevice *dev, uint64_t cnt, int family)
 #ifdef BUILD_UNIX_SOCKET
 TmEcode LiveDeviceGetBypassedStats(json_t *cmd, json_t *answer, void *data)
 {
-    LiveDevice *ldev = NULL, *ndev;
+    LiveDevice *ldev = NULL, *ndev = NULL;
 
     json_t *ifaces = NULL;
     while(LiveDeviceForEach(&ldev, &ndev)) {