doc: in go1.5.html fix claim about linking for ppc64(le)?

Change-Id: If61c2063a8b63f0e3e498a5e86803b5ddba9fa3c
Reviewed-on: https://go-review.googlesource.com/12886Reviewed-by: Austin Clements <austin@google.com>

doc/go1.5.html

@@ -236,9 +236,8 @@ is only supported using external linking.
 <p>
 Also available as experiments are <code>ppc64</code> (IBM Power 64)
 and <code>ppc64le</code> (IBM Power 64, little-endian).
-Both these ports support <code>cgo</code>,
-but for <code>ppc64</code> it requires external linking while
-for <code>ppc64le</code> it requires internal linking.
+Both these ports support <code>cgo</code> but
+only with internal linking.
 </p>
 
 <p>