ref-manual: Applied a correction to the GCC 5 migration 2.0 section.

Added an exception and link to a patch the user should use if they
are using GCC 5 for specific ARM machine.

(From yocto-docs rev: 4f43b683cf4a078c6df4b8c6be59e6fb8702d265)

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

documentation/ref-manual/migration.xml

@@ -2332,6 +2332,21 @@
             of other recipes.
         </para>
 
+        <para>
+            One important example is a fix for when the Linux kernel freezes at
+            boot time on ARM when built with GCC 5.
+            If you are using your own kernel recipe or source tree and
+            building for ARM, you will likely need to apply this
+            <ulink url='https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=a077224fd35b2f7fbc93f14cf67074fc792fbac2'>patch</ulink>.
+            The standard <filename>linux-yocto</filename> kernel source tree
+            already has a workaround for the same issue.
+        </para>
+
+        <para>
+            For further details, please see
+            <ulink url='https://gcc.gnu.org/gcc-5/changes.html'></ulink>.
+        </para>
+
         <para>
             Alternatively, you can switch back to GCC 4.9 or 4.8 by
             setting <filename>GCCVERSION</filename> in your configuration,
@@ -2339,8 +2354,6 @@
             <literallayout class='monospaced'>
      GCCVERSION = "4.9%"
             </literallayout>
-            For further details, please see
-            <ulink url='https://gcc.gnu.org/gcc-5/changes.html'></ulink>.
         </para>
     </section>