[2.4 PATCH] DDB5xxx update and rockhopper II support

Ralf,

This patch is an update for DDB5xxx boards.  It adds support to the latest 
rockhopper II baseboard.  A couple of nice new features are added as well, 
such as automatical run-time board detection and bus frequency detection, etc.

Credits should go to Brad LeRonde and Alice Hennessy who did much of the work 
in this patch.

This patch does not apply to 2.5.  I will create one or more new patches later 
for 2.5.

Jun