sdk-manual: Updated link to variables set for cross-toolchain script

The link was going to a spot from which another link was suggested.
Too many redirections for the reader.  Linked to the original place
instead.

(From yocto-docs rev: 9983cecb37f179a8eef28ab20a6539f8af100978)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/sdk-manual/sdk-working-projects.xml

@@ -274,9 +274,9 @@
                     </para></listitem>
             </itemizedlist>
             <note>
-                For the list of variables set up by the cross-toolchain
+                For information on the variables set up by the cross-toolchain
                 environment setup script, see the
-                "<link linkend='sdk-running-the-sdk-environment-setup-script'>Running the SDK Environment Setup Script</link>"
+                "<link linkend='sdk-running-the-extensible-sdk-environment-setup-script'>Running the Extensible SDK Environment Setup Script</link>"
                 section.
             </note>
         </para>