Fix macroization of inline in C++

When compiling as C++, MSVC complains about our macroization of a keyword.
Stop doing that as we know inline is always available in C++
diff --git a/ChangeLog b/ChangeLog
index 68b1255..c596908 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,9 @@
 
 = mbed TLS 2.1.2 released 2015-10-xx
 
+Bugfix
+   * Fix macroization of 'inline' keywork when building as C++. (#279)
+
 Changes
    * Fixed paths for check_config.h in example config files. (Found by bachp)
      (#291)