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/cobra5272/u-boot.lds b/board/cobra5272/u-boot.lds
index 7e716bb..8989880 100644
--- a/board/cobra5272/u-boot.lds
+++ b/board/cobra5272/u-boot.lds
@@ -56,7 +56,7 @@
     /* the sector layout of our flash chips!	XXX FIXME XXX	*/
     cpu/mcf52x2/start.o		(.text)
     cpu/mcf52x2/cpu_init.o	(.text)
-    lib_m68k/traps.o		(.text)
+    arch/m68k/lib/traps.o		(.text)
     cpu/mcf52x2/interrupts.o	(.text)
     common/dlmalloc.o		(.text)
     lib_generic/zlib.o		(.text)