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/ivm/u-boot.lds.debug b/board/ivm/u-boot.lds.debug
index b5206c5..17965a0 100644
--- a/board/ivm/u-boot.lds.debug
+++ b/board/ivm/u-boot.lds.debug
@@ -59,7 +59,7 @@
     common/dlmalloc.o	(.text)
     lib_generic/vsprintf.o	(.text)
     lib_generic/crc32.o		(.text)
-    lib_ppc/extable.o	(.text)
+    arch/ppc/lib/extable.o	(.text)
 
     . = env_offset;
     common/env_embedded.o(.text)