[patch][wwwdocs] gcc 4.9 changes - AMD new cores

[Gopalasubramanian, Ganesh]

Hello, 

This patch adds details about new AMD cores that got enabled in GCC-4.9.
OK for the wwwdocs? 

Regards
Ganesh

cvs diff: Diffing .
Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.9/changes.html,v
retrieving revision 1.44
diff -r1.44 changes.html
404a405,407
>     <li>Support for new AMD family 15h processors (Excavator core)
>         is now available through the <code>-march=bdver4</code> and
>         <code>-mtune=bdver4</code> options.</li>