wwwdocs: An additional release note for powerpc for GCC 8

[Kelvin Nilsen]

Is this revision to the existing draft GCC 8 release notes ok for
commit?  

Thanks

? cvs.diffs
Index: htdocs/gcc-8/changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-8/changes.html,v
retrieving revision 1.36
diff -u -3 -p -r1.36 changes.html
--- htdocs/gcc-8/changes.html	12 Feb 2018 07:23:11 -0000	1.36
+++ htdocs/gcc-8/changes.html	14 Feb 2018 14:58:56 -0000
@@ -464,6 +464,11 @@ a work-in-progress.</h2>
     <code>powerpc-xilinx-eabi*</code>)
     is deprecated and will be removed in a future release.
   </li>
+  <li>
+    Support for using big-endian AltiVec intrinsics on a little-endian target
+    (<code>-maltivec=be</code>) is deprecated and will be removed in a
+    future release.
+  </li>
 </ul>
 
 <h3 id="powerpcspe">PowerPC SPE</h3>