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/freescale/mpc7448hpc2/tsi108_init.c b/board/freescale/mpc7448hpc2/tsi108_init.c
index c6a3ade..e1c63f8 100644
--- a/board/freescale/mpc7448hpc2/tsi108_init.c
+++ b/board/freescale/mpc7448hpc2/tsi108_init.c
@@ -323,7 +323,7 @@
 	 * We will over-ride the env_init called in board_init_f
 	 * This is really a work-around because, the HLP bank 1
 	 * where NVRAM resides is not visible during board_init_f
-	 * (arch/ppc/lib/board.c)
+	 * (arch/powerpc/lib/board.c)
 	 * Alternatively, we could use the I2C EEPROM at start-up to configure
 	 * and enable all HLP banks and not just HLP 0 as is being done for
 	 * Taiga Rev. 2.