nl80211: Work around error case prints for nl_recvmsgs on Android

I got the below prints on a particular Android platform:

I/wpa_supplicant( 2637): nl80211: send_and_recv->nl_recvmsgs failed: 20
I/wpa_supplicant( 2637): nl80211: send_and_recv->nl_recvmsgs failed: 20

In JellyBean libnl_2 code, I see that the nl_recvmsgs returns postive values
too. In some cases, nl_recvmgs return the output of nl_recv function. nl_recv
function can return Number of bytes read, 0 or a negative error code.

Looks like this positive return value for nl_recvmsgs may be specific to
Android. While this is not how the API is supposed to work, this does no
harm with upstream libnl which returns only 0 or -1 from the function.

Signed-off-by: Jithu Jance <jithu@broadcom.com>

src/drivers/driver_nl80211.c

@@ -652,7 +652,7 @@ static int send_and_recv(struct nl80211_global *global,
 
 	while (err > 0) {
 		int res = nl_recvmsgs(nl_handle, cb);
-		if (res) {
+		if (res < 0) {
 			wpa_printf(MSG_INFO,
 				   "nl80211: %s->nl_recvmsgs failed: %d",
 				   __func__, res);
@@ -910,7 +910,7 @@ static void nl80211_recv_beacons(int sock, void *eloop_ctx, void *handle)
 	wpa_printf(MSG_EXCESSIVE, "nl80211: Beacon event message available");
 
 	res = nl_recvmsgs(handle, w->nl_cb);
-	if (res) {
+	if (res < 0) {
 		wpa_printf(MSG_INFO, "nl80211: %s->nl_recvmsgs failed: %d",
 			   __func__, res);
 	}
@@ -3276,7 +3276,7 @@ static void wpa_driver_nl80211_event_receive(int sock, void *eloop_ctx,
 	wpa_printf(MSG_MSGDUMP, "nl80211: Event message available");
 
 	res = nl_recvmsgs(handle, cb);
-	if (res) {
+	if (res < 0) {
 		wpa_printf(MSG_INFO, "nl80211: %s->nl_recvmsgs failed: %d",
 			   __func__, res);
 	}