[media] v4l2-dv-timings: add module name, description, license

I completely forgot to add them when I made this module. Loading this module
without it will taint the kernel, which is not intended.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: stable@vger.kernel.org      # for v3.12 and up
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>