media: v4l: subdev: Also return pads array information on stream functions

There are two sets of functions that return information from sub-device
state, one for stream-unaware users and another for stream-aware users.
Add support for stream-aware functions to return format, crop and compose
information from pad-based array that are functionally equivalent to the
old, stream-unaware ones.

Also check state is non-NULL, in order to guard against old drivers
potentially calling this with NULL state for active formats or selection
rectangles.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>