media: v4l: uAPI doc: Simplify NATIVE_SIZE selection target documentation

The NATIVE_SIZE target is documented for mem2mem devices but no driver has
ever apparently used it. It may be never needed; remove it for now.
Suggested-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/media/uapi/v4l/v4l2-selection-targets.rst

@@ -42,12 +42,7 @@ of the two interfaces they are used.
     * - ``V4L2_SEL_TGT_NATIVE_SIZE``
       - 0x0003
       - The native size of the device, e.g. a sensor's pixel array.
-	``left`` and ``top`` fields are zero for this target. Setting the
-	native size will generally only make sense for memory to memory
-	devices where the software can create a canvas of a given size in
-	which for example a video frame can be composed. In that case
-	V4L2_SEL_TGT_NATIVE_SIZE can be used to configure the size of
-	that canvas.
+	``left`` and ``top`` fields are zero for this target.
       - Yes
       - Yes
     * - ``V4L2_SEL_TGT_COMPOSE``