[media] media/v4l2-ctrls: Code cleanout validate_new()

We can simplify the code removing the if().

v4l2_ctr_new sets ctrls->elems to 1 when !ctrl->is_ptr.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>