Move lib_$ARCH directories to arch/$ARCH/lib

Also move lib_$ARCH/config.mk to arch/$ARCH/config.mk

This change is intended to clean up the top-level directory structure
and more closely mimic Linux's directory organization.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/actux2/u-boot.lds b/board/actux2/u-boot.lds
index 0752656..543af30 100644
--- a/board/actux2/u-boot.lds
+++ b/board/actux2/u-boot.lds
@@ -33,7 +33,7 @@
 		cpu/ixp/start.o(.text)
 		lib_generic/string.o(.text)
 		lib_generic/vsprintf.o(.text)
-		lib_arm/board.o(.text)
+		arch/arm/lib/board.o(.text)
 		common/dlmalloc.o(.text)
 		cpu/ixp/cpu.o(.text)