modem: simcom-sim7080: fix handling failed fragment send in sendmsg()

If one data fragment was not sent successfully in sendmsg(), then
attempting to send the rest does not make any sense, as it would introduce
hole in data stream.

Currently if one fragment was not sent successfully, then there is a
'break' in inner loop, but that moves the execution to sending the
following data fragments.

Return early in case of fragment sending failure, so that there are no more
send attempts.

Signed-off-by: Marcin Niestroj <[email protected]>

Author: mniestroj

drivers/modem/simcom-sim7080.c

@@ -468,8 +468,7 @@ static ssize_t offload_sendmsg(void *obj, const struct msghdr *msg, int flags)
 				if (ret == -EAGAIN) {
 					k_sleep(K_SECONDS(1));
 				} else {
-					sent = ret;
-					break;
+					return ret;
 				}
 			} else {
 				sent += ret;