Remove armv4t support.

This was never finished, and hasn't been maintained. And the hardware's
totally obsolete.

Change-Id: Icbf78e507de3b8be8a8f995b8423cc3c678ab0d3
diff --git a/docs/porting-guide.html b/docs/porting-guide.html
index d23b903..3e33d13 100644
--- a/docs/porting-guide.html
+++ b/docs/porting-guide.html
@@ -234,8 +234,8 @@
 </p><p>
 If you're working on a variation of an existing architecture, you may be
 able to use most of the existing code and just provide replacements for
-a few instructions.  Look at the <code>armv4t</code> implementation as
-an example.
+a few instructions.  Look at the <code>vm/mterp/config-*</code> files
+for examples.
 </p>