net: lwm2m: Cleanup special handling of DNS for offloading

With `CONFIG_NET_NATIVE`, offloaded drivers can specify capabilites with
`NET_IPV4/6` configs, so there is no longer need to handle socket
offloading separately.

Also, initialize hints structure with zeros, as according to man pages
unused fields should be set to 0:
`All the other fields in the structure pointed to by hints must contain
either 0 or a NULL pointer, as appropriate.`

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

subsys/net/lib/lwm2m/lwm2m_engine.c

@@ -4203,7 +4203,7 @@ int lwm2m_parse_peerinfo(char *url, struct sockaddr *addr, bool *use_dtls)
 {
 	struct http_parser_url parser;
 #if defined(CONFIG_LWM2M_DNS_SUPPORT)
-	struct addrinfo hints, *res;
+	struct addrinfo *res, hints = { 0 };
 #endif
 	int ret;
 	u16_t off, len;
@@ -4270,9 +4270,6 @@ int lwm2m_parse_peerinfo(char *url, struct sockaddr *addr, bool *use_dtls)
 		hints.ai_family = AF_INET6;
 #elif defined(CONFIG_NET_IPV4)
 		hints.ai_family = AF_INET;
-#elif defined(CONFIG_NET_SOCKETS_OFFLOAD)
-		memset(&hints, 0, sizeof(hints));
-		hints.ai_family = AF_INET;
 #else
 		hints.ai_family = AF_UNSPEC;
 #endif /* defined(CONFIG_NET_IPV6) && defined(CONFIG_NET_IPV4) */