[media] drxd, siano: Remove unused include linux/version.h

Both drxd and siano drivers were including linux/version.h without
any reason. Probably, this is due to some compatibility code that
used to exist before having their support added into the Linux
Kernel.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>