Simplify net_accept() with UDP sockets

This is made possible by the new API where net_accept() gets a pointer to
bind_ctx, so it can update it.
diff --git a/ChangeLog b/ChangeLog
index 7c238e5..f87f1e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -174,6 +174,8 @@
      instead, see mbedtls_ssl_set_timer_cb(), with the Timing module providing
      an example implementation, see mbedtls_timing_delay_context and
      mbedtls_timing_set/get_delay().
+   * With UDP sockets, it is no longer necessary to call net_bind() again
+     after a successful net_accept().
 
 Changes
    * mbedtls_ctr_drbg_random() and mbedtls_hmac_drbg_random() are now