Move arch/ppc to arch/powerpc

As discussed on the list, move "arch/ppc" to "arch/powerpc" to
better match the Linux directory structure.

Please note that this patch also changes the "ppc" target in
MAKEALL to "powerpc" to match this new infrastructure. But "ppc"
is kept as an alias for now, to not break compatibility with
scripts using this name.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
Acked-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Peter Tyser <ptyser@xes-inc.com>
Cc: Anatolij Gustschin <agust@denx.de>
diff --git a/board/netphone/u-boot.lds.debug b/board/netphone/u-boot.lds.debug
index ec479b1..df7b6ad 100644
--- a/board/netphone/u-boot.lds.debug
+++ b/board/netphone/u-boot.lds.debug
@@ -55,7 +55,7 @@
     /* WARNING - the following is hand-optimized to fit within	*/
     /* the sector layout of our flash chips!	XXX FIXME XXX	*/
 
-    arch/ppc/cpu/mpc8xx/start.o		(.text)
+    arch/powerpc/cpu/mpc8xx/start.o		(.text)
     common/dlmalloc.o		(.text)
     lib/vsprintf.o	(.text)
     lib/crc32.o		(.text)