Update the openrisc previous program counter (ppc) when running code in the cgen based simulator.

* or1kcommon.cpu: Add pc set semantics to also update ppc.

cpu/ChangeLog

@@ -1,3 +1,7 @@
+2017-03-15  Stafford Horne  <shorne@gmail.com>
+
+	* or1kcommon.cpu: Add pc set semantics to also update ppc.
+
 2016-10-06  Alan Modra  <amodra@gmail.com>
 
 	* mep.opc (expand_string): Add fall through comment.

cpu/or1kcommon.cpu

@@ -26,6 +26,11 @@
   (comment "program counter")
   (attrs PC (MACH ORBIS-MACHS))
   (type pc UWI)
+  (get () (raw-reg h-pc))
+  (set (newval) (sequence ()
+                 (set (reg h-sys-ppc) (raw-reg h-pc))
+                 (set (raw-reg h-pc) newval)
+                ))
   )
 
 (define-pmacro REG-INDICES