mtd: fix warnings due to 64-bit partition support

commit 39ac34473f3c96e77cbe03a49141771ed1639486 ("cmd_mtdparts: use 64
bits for flash size, partition size & offset") introduced warnings
in a couple places due to printf formats or pointer casting.

This patch fixes the warnings pointed out here:
http://lists.denx.de/pipermail/u-boot/2013-October/164981.html

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: York Sun <yorksun@freescale.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Tom Rini <trini@ti.com>
diff --git a/fs/cramfs/cramfs.c b/fs/cramfs/cramfs.c
index e578a1e..fd8e4ef 100644
--- a/fs/cramfs/cramfs.c
+++ b/fs/cramfs/cramfs.c
@@ -43,9 +43,10 @@
  * device address space offset, so we need to shift it by a device start address. */
 #if !defined(CONFIG_SYS_NO_FLASH)
 extern flash_info_t flash_info[];
-#define PART_OFFSET(x)	(x->offset + flash_info[x->dev->id->num].start[0])
+#define PART_OFFSET(x)	((ulong)x->offset + \
+			 flash_info[x->dev->id->num].start[0])
 #else
-#define PART_OFFSET(x)	(x->offset)
+#define PART_OFFSET(x)	((ulong)x->offset)
 #endif
 
 static int cramfs_read_super (struct part_info *info)