media: i2c: imx219: Declare that the driver can create events

The flag V4L2_SUBDEV_FL_HAS_EVENTS is required if the subdev can
generate events. It can create events from the ctrl handler, therefore
this is required.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>