media: i2c: max9286: Rework comments in .bound()

Rephrase a comment in .bound() callback to make it clear we register
a subdev notifier and remove a redundant comment about disabling i2c
auto-ack.

No functional changes intended.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>