drm/sti: hdmi fix i2c adapter device refcounting

The commit 53bdcf5f ("drm: sti: fix sub-components bind") moves
i2c adapter search and locking from .bind() to .probe(), however
proper error path in the modified .probe() is not implemented and
leftover of the related error path in .bind() remains. This change
fixes these issues.

Fixes: 53bdcf5f ("drm: sti: fix sub-components bind")
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Vincent Abriou <vincent.abriou@st.com>