media: i2c: ov9640: fix missing error handling in probe

Control handlers registration lacked error path with
v4l2_ctrl_handler_free() call. Fix it by using goto to alread existing
v4l2_ctrl_handler_free() call.

Signed-off-by: Petr Cvek <petrcvekcz@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>