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/doc/README.mpc5xx b/doc/README.mpc5xx
index 07be863..2e12174 100644
--- a/doc/README.mpc5xx
+++ b/doc/README.mpc5xx
@@ -34,9 +34,9 @@
 u-boot-0.2.0/include/status_led.h
 u-boot-0.2.0/include/asm-ppc/u-boot.h
 u-boot-0.2.0/include/asm-ppc/5xx_immap.h
-u-boot-0.2.0/lib_ppc/board.c
-u-boot-0.2.0/lib_ppc/cache.c
-u-boot-0.2.0/lib_ppc/time.c
+u-boot-0.2.0/arch/ppc/lib/board.c
+u-boot-0.2.0/arch/ppc/lib/cache.c
+u-boot-0.2.0/arch/ppc/lib/time.c
 u-boot-0.2.0/Makefile
 u-boot-0.2.0/CREDITS
 u-boot-0.2.0/doc/README.mpc5xx