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/amirix/ap1000/u-boot.lds b/board/amirix/ap1000/u-boot.lds
index 707203d..10308d5 100644
--- a/board/amirix/ap1000/u-boot.lds
+++ b/board/amirix/ap1000/u-boot.lds
@@ -65,7 +65,7 @@
     cpu/ppc4xx/speed.o	(.text)
     common/dlmalloc.o	(.text)
     lib_generic/crc32.o		(.text)
-    lib_ppc/extable.o	(.text)
+    arch/ppc/lib/extable.o	(.text)
     lib_generic/zlib.o		(.text)
 
 /*    . = env_offset;*/