After discussing with Hans, change pwc to use the default version
control.

The only version ever used for pwc driver is 10.0.12, due to
commit 2b455db6.

Changing it to 3.x.y won't conflict with the old version.
There's no namespace conflicts in any predictable future.

Even on the remote far-away case where we might have a conflict,
it will be on just one specific stable Kernel release (Kernel 10.0.12),
if we ever have such stable release.

So, it is safe and consistent on using 3.x.y numering schema for
it.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>