Update GCC 4.9 changes.html

[H.J. Lu]

Hi,

This patch adds Intel microarchitecture changes to GCC 4.9 changes.html.
OK to install?

Thanks.

-- 
H.J.
--
Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.9/changes.html,v
retrieving revision 1.49
diff -u -p -r1.49 changes.html
--- changes.html    18 Dec 2013 02:20:47 -0000    1.49
+++ changes.html    27 Dec 2013 11:26:42 -0000
@@ -393,7 +393,15 @@ auto incr = [](auto x) { return x++; };
       >Function Multiversioning</a>.
     </li>
     <li>GCC now supports the new Intel microarchitecture named Silvermont
-      through <code>-march=slm</code>.
+      through <code>-march=silvermont</code>.
+    </li>
+    <li>GCC now supports the new Intel microarchitecture named Broadwell
+      through <code>-march=broadwell</code>.
+    </li>
+    <li>Optimizing for other Intel microarchitectures have been renamed
+      to <code>-march=nahelam</code>, <code>westmere</code>,
+      <code>sandybridge</code>, <code>ivybridge</code>,
+      <code>haswell</code>, <code>bonnell</code>.
     </li>
     <li><code>-march=generic</code> has been retuned for better support of
       Intel core and AMD Bulldozer architectures.  Performance of AMD K7, K8,