Indicate correct range of relative branches

The range of a long relative branch is described to be 2 GB in each
direction, while it's actually 4 GB in each direction.  Correct that.

lzsabi.tex

@@ -3483,8 +3483,8 @@ \subsection{Branching}
 variety of branch instructions.  The most commonly used of these
 performs a self-relative jump with a 128-Kbyte range (up to 64 Kbytes
 in either direction).  {\ifzseries For large functions, another
-  self-relative jump is available with a range of 4$\,$Gbytes (up to
-  2$\,$Gbytes in either direction).\fi}%
+  self-relative jump is available with a range of 8$\,$Gbytes (up to
+  4$\,$Gbytes in either direction).\fi}%
 
 \begin{table}
   \centering