arm: marvell: Move arch/kirkwood.h to arch/soc.h

This move makes is possible to use this header not only from kirkwood
platforms but from all Marvell mvebu platforms.

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Luka Perkov <luka@openwrt.org>
Acked-by: Prafulla Wadaskar <prafulla@marvell.com>
diff --git a/board/Marvell/dreamplug/dreamplug.c b/board/Marvell/dreamplug/dreamplug.c
index b53c810..3c286be 100644
--- a/board/Marvell/dreamplug/dreamplug.c
+++ b/board/Marvell/dreamplug/dreamplug.c
@@ -12,7 +12,7 @@
 #include <common.h>
 #include <miiphy.h>
 #include <asm/arch/cpu.h>
-#include <asm/arch/kirkwood.h>
+#include <asm/arch/soc.h>
 #include <asm/arch/mpp.h>
 #include "dreamplug.h"