fs/affs/super.c: fix sparse warning

Index: linux-2.6.11-bk2-sparse/fs/affs/super.c
===================================================================
@@ -421,11 +421,11 @@ got_root:
 	}
 
 	if (mount_flags & SF_VERBOSE) {
-		chksum = cpu_to_be32(chksum);
+		__be32 chksum1 = cpu_to_be32(chksum);
 		printk(KERN_NOTICE "AFFS: Mounting volume \"%*s\": Type=%.3s\\%c, Blocksize=%d\n",
 			AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0],
 			AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
-			(char *)&chksum,((char *)&chksum)[3] + '0',blocksize);
+			(char *)&chksum1,((char *)&chksum1)[3] + '0',blocksize);
 	}
 
 	sb->s_flags |= MS_NODEV | MS_NOSUID;