[media] media: tw686x: Support frame sizes and frame intervals enumeration

This commit adds support for VIDIOC_ENUM_FRAMESIZES
and VIDIOC_ENUM_FRAMEINTERVALS enumeration ioctls.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>