tests: net: socket: Fix function signature

Update the process_dns function signature to match the expected
k_thread_entry_t type:
typedef void (*k_thread_entry_t)(void *p1, void *p2, void *p3);

Signed-off-by: Tim Pambor <tim.pambor@codewrights.de>

tests/net/socket/getaddrinfo/src/main.c

@@ -108,8 +108,12 @@ static bool check_dns_query(uint8_t *buf, int buf_len)
 	return true;
 }
 
-static int process_dns(void)
+static void process_dns(void *p1, void *p2, void *p3)
 {
+	ARG_UNUSED(p1);
+	ARG_UNUSED(p2);
+	ARG_UNUSED(p3);
+
 	struct zsock_pollfd pollfds[2];
 	struct sockaddr *addr;
 	socklen_t addr_len;
@@ -164,8 +168,6 @@ static int process_dns(void)
 			}
 		}
 	}
-
-	return -errno;
 }
 
 K_THREAD_DEFINE(dns_server_thread_id, STACK_SIZE,