Add OpenCL blurb to release notes.

llvm-svn: 145270

llvm/docs/ReleaseNotes.html

@@ -133,6 +133,10 @@ Release Notes</a>.</h1>
     Objective-C runtime, or version 1.6 or later of the GNUstep Objective-C
     runtime version.</li>
 
+  <li>Improved support for OpenCL C, including the <tt>vec_step</tt> operator,
+      address space qualifiers, improved vector literal support and code
+      generation support for the <a href="#PTX">PTX target</a>.</li>
+
   <li>Implemented a number of optimizations in <tt>libclang</tt>, the Clang C
       interface, to improve the performance of code completion and the mapping
       from source locations to abstract syntax tree nodes.</li>