[media] media: imx: capture: add frame sizes/interval enumeration

Add support for enumerating frame sizes and frame intervals from the
first subdev via the V4L2 interfaces.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>