jfs: agstart field must be 64 bits

The previous patch added the agstart field to jfs_ip, but declared
it a long.  We need to make sure its 64 bits on every platform.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

fs/jfs/jfs_incore.h

@@ -50,7 +50,7 @@ struct jfs_inode_info {
 	short	btindex;	/* btpage entry index*/
 	struct inode *ipimap;	/* inode map			*/
 	unsigned long cflag;	/* commit flags		*/
-	long	agstart;	/* agstart of the containing IAG */
+	u64	agstart;	/* agstart of the containing IAG */
 	u16	bxflag;		/* xflag of pseudo buffer?	*/
 	unchar	pad;
 	signed char active_ag;	/* ag currently allocating from	*/