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/include/common.h b/include/common.h
index a133e34..7aa910d 100644
--- a/include/common.h
+++ b/include/common.h
@@ -230,7 +230,7 @@
 void	init_cmd_timeout(void);
 void	reset_cmd_timeout(void);
 
-/* lib_$(ARCH)/board.c */
+/* arch/$(ARCH)/lib/board.c */
 void	board_init_f  (ulong) __attribute__ ((noreturn));
 void	board_init_r  (gd_t *, ulong) __attribute__ ((noreturn));
 int	checkboard    (void);
@@ -604,17 +604,17 @@
 /* $(CPU)/.../video.c */
 ulong	video_setmem (ulong);
 
-/* lib_$(ARCH)/cache.c */
+/* arch/$(ARCH)/lib/cache.c */
 void	flush_cache   (unsigned long, unsigned long);
 void	flush_dcache_range(unsigned long start, unsigned long stop);
 void	invalidate_dcache_range(unsigned long start, unsigned long stop);
 
 
-/* lib_$(ARCH)/ticks.S */
+/* arch/$(ARCH)/lib/ticks.S */
 unsigned long long get_ticks(void);
 void	wait_ticks    (unsigned long);
 
-/* lib_$(ARCH)/time.c */
+/* arch/$(ARCH)/lib/time.c */
 void	__udelay      (unsigned long);
 ulong	usec2ticks    (unsigned long usec);
 ulong	ticks2usec    (unsigned long ticks);