[media] i2c: ov2659: signedness bug inov2659_set_fmt()

This needs to be signed or there is a risk of hitting a forever loop.

Fixes: c4c0283a ('[media] media: i2c: add support for omnivision's ov2659 sensor')

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>