drm/tilcdc: fix typos in comment

Fix typos in comment.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Signed-off-by: Jyri Sarha <jyri.sarha@iki.fi>
Link: https://patchwork.freedesktop.org/patch/msgid/1650625751-32137-1-git-send-email-brookxu.cn@gmail.com