Add value for Read Encryption Key Size command constant
diff --git a/lib/hci.c b/lib/hci.c
index b4511e1..e53d3ce 100644
--- a/lib/hci.c
+++ b/lib/hci.c
@@ -495,7 +495,7 @@
 	{ "Reserved",					161 },
 	{ "Send Keypress Notification",			162 },
 	{ "IO Capabilities Response Negative Reply",	163 },
-	{ "Reserved",					164 },
+	{ "Read Encryption Key Size",			164 },
 	{ "Reserved",					165 },
 	{ "Reserved",					166 },
 	{ "Reserved",					167 },