nios: Move cpu/nios/* to arch/nios/cpu/*

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/doc/README.nios b/doc/README.nios
index da30ff5..5628144 100644
--- a/doc/README.nios
+++ b/doc/README.nios
@@ -243,7 +243,7 @@
 	following commands, then close the console window:
 
 		(gdb) directory common
-		(gdb) directory cpu/nios
+		(gdb) directory arch/nios/cpu
 		(gdb) directory arch/nios/lib
 		(gdb) directory board/altera/dk1c20