media: i2c: max96717: clean up on error in max96717_subdev_init()

[ Upstream commit d56786977ba11ed15b066495c1363889bcb1c3bb ]

Call v4l2_ctrl_handler_free() to clean up from v4l2_ctrl_handler_init().

Fixes: 19b5e551 ("media: i2c: max96717: add test pattern ctrl")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Julien Massot <julien.massot@collabora.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>