Fix issue #8215 : add missing requires documentation in mbedtls_config.h

Add missing requirements MBEDTLS_SSL_PROTO_TLS1_2 to option MBEDTLS_SSL_RENEGOTIATION documentation.

Signed-off-by: jnmeurisse <88129653+jnmeurisse@users.noreply.github.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 314dac6..7d94329 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1672,6 +1672,8 @@
  * it has been associated with security issues in the past and is easy to
  * misuse/misunderstand.
  *
+ * Requires: MBEDTLS_SSL_PROTO_TLS1_2
+ *
  * Comment this to disable support for renegotiation.
  *
  * \note   Even if this option is disabled, both client and server are aware