ext4: reduce arguments of ext4_fc_add_dentry_tlv

Let's pass fc_dentry directly since those arguments (tag, parent_ino and
ino etc) can be deferenced from it.

Signed-off-by: Guoqing Jiang <jiangguoqing@kylinos.cn>
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210727080708.3708814-1-guoqing.jiang@linux.dev