arm: Move cpu/$CPU to arch/arm/cpu/$CPU

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/actux4/config.mk b/board/actux4/config.mk
index 9a634cd..f2b5fc9 100644
--- a/board/actux4/config.mk
+++ b/board/actux4/config.mk
@@ -1,4 +1,4 @@
 TEXT_BASE = 0x00e00000
 
 # include NPE ethernet driver
-BOARDLIBS = cpu/ixp/npe/libnpe.a
+BOARDLIBS = arch/arm/cpu/ixp/npe/libnpe.a