ssl_cache: Add getter access to timeout field

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/include/mbedtls/ssl_cache.h b/include/mbedtls/ssl_cache.h
index 08f98b5..b1b4250 100644
--- a/include/mbedtls/ssl_cache.h
+++ b/include/mbedtls/ssl_cache.h
@@ -160,6 +160,20 @@
  * \param timeout  cache entry timeout in seconds
  */
 void mbedtls_ssl_cache_set_timeout(mbedtls_ssl_cache_context *cache, int timeout);
+
+/**
+ * \brief          Get the cache timeout
+ *
+ *                 A timeout of 0 indicates no timeout.
+ *
+ * \param cache    SSL cache context
+ *
+ * \return         cache entry timeout in seconds
+ */
+static inline int mbedtls_ssl_cache_get_timeout(mbedtls_ssl_cache_context *cache)
+{
+    return cache->MBEDTLS_PRIVATE(timeout);
+}
 #endif /* MBEDTLS_HAVE_TIME */
 
 /**