[media] gspca: don't include linux/version.h

Instead of handling a per-driver driver version, use the
per-subsystem one.

As reviewed by Jean-Francois Moine <moinejf@free.fr>:
	- the 'info' may be simplified:

Reviewed-by: Jean-Francois Moine <moinejf@free.fr>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>