Improve comment

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index f3e5a0a..e2f6d77 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2695,8 +2695,8 @@
 
     /*
      * We may have not been able to send to the peer all the handshake data
-     * that were written into the output buffer by the previous handshake step:
-     * the write to the network callback returned with the
+     * that were written into the output buffer by the previous handshake step,
+     * if the write to the network callback returned with the
      * #MBEDTLS_ERR_SSL_WANT_WRITE error code.
      * We proceed to the next handshake step only when all data from the
      * previous one have been sent to the peer, thus we make sure that this is