Change version number to 2.2.1

Changed version for library files and yotta module
diff --git a/ChangeLog b/ChangeLog
index 7f6584c..e21187f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,6 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
-= mbed TLS 2.2.1 released 2015-12-xx
+= mbed TLS 2.2.1 released 2016-01-05
 
 Security
    * Fix potential double free when mbedtls_asn1_store_named_data() fails to