Write-only ioctls should have a const argument in the ioctl op.
Do this conversion for vidioc_s_modulator.
Adding const for write-only ioctls was decided during the 2012 Media Workshop.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>