media: cec: Fix debugfs leak on bus_register() failure

media: cec: Fix debugfs leak on bus_register() failure

In cec_devnode_init(), the debugfs directory created with
debugfs_create_dir() is not removed if bus_register() fails.
This leaves a stale "cec" entry in debugfs and prevents
proper module reloading.

Fix this by removing the debugfs directory in the error path.

Fixes: a56960e8b406 ("[media] cec: add HDMI CEC framework (core)")
Cc: stable@vger.kernel.org
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>