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/drivers/mtd/nand/kirkwood_nand.c b/drivers/mtd/nand/kirkwood_nand.c
index 3e5fb0c..4fc34d6 100644
--- a/drivers/mtd/nand/kirkwood_nand.c
+++ b/drivers/mtd/nand/kirkwood_nand.c
@@ -8,7 +8,7 @@
 
 #include <common.h>
 #include <asm/io.h>
-#include <asm/arch/kirkwood.h>
+#include <asm/arch/soc.h>
 #include <nand.h>
 
 /* NAND Flash Soc registers */