[media] v4l2-common: remove obsolete check for ' at the end of a driver name

During the transition to sub-devices several years ago non-subdev drivers
had a ' at the end of their driver name to tell them apart from already
converted drivers. This check was a left-over from that time and can be
removed.

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