Fix inaccurate comment in sample DTLS server

Signed-off-by: Ryan LaPointe <ryan@ryanlapointe.org>
diff --git a/programs/ssl/dtls_server.c b/programs/ssl/dtls_server.c
index c3b073e..cebeffa 100644
--- a/programs/ssl/dtls_server.c
+++ b/programs/ssl/dtls_server.c
@@ -114,7 +114,7 @@
 #include "mbedtls/ssl_cache.h"
 #endif
 
-#define READ_TIMEOUT_MS 10000   /* 5 seconds */
+#define READ_TIMEOUT_MS 10000   /* 10 seconds */
 #define DEBUG_LEVEL 0