Fix doxygen comment parameter name

Signed-off-by: Max Fillinger <max@max-fillinger.net>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index e847022..5dc3d52 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -5770,7 +5770,7 @@
  /**
   * \brief             TLS-Exporter to derive shared symmetric keys between server and client.
   *
-  * \param ctx         SSL context from which to export keys. Must have finished the handshake.
+  * \param ssl         SSL context from which to export keys. Must have finished the handshake.
   * \param out         Output buffer of length at least key_len bytes.
   * \param key_len     Length of the key to generate in bytes. Must be < 2^16 in TLS 1.3.
   * \param label       Label for which to generate the key of length label_len.