fat: fix uninitialized variable

syszbot produced this with a corrupted fs image.  In theory, however an IO
error would trigger this also.

This affects just an error report, so should not be a serious error.

Link: https://lkml.kernel.org/r/87r08wjsnh.fsf@mail.parknet.co.jp
Link: https://lkml.kernel.org/r/66ff2c95.050a0220.49194.03e9.GAE@google.com
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: syzbot+ef0d7bc412553291aa86@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/fat/namei_vfat.c

@@ -1037,7 +1037,7 @@ static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (corrupt < 0) {
 		fat_fs_error(new_dir->i_sb,
 			     "%s: Filesystem corrupted (i_pos %lld)",
-			     __func__, sinfo.i_pos);
+			     __func__, new_i_pos);
 	}
 	goto out;
 }