drivers: video: introduce buffer flags for fragmented frames

Video buffers did not precise whether they contained a whole frame,
or a fragment of a frame.

Adding a flag struct as well as a total frame field allows video
devices to tell whether they produced

- a complete frame (with VIDEO_BUF_EOF and no VIDEO_BUF_FRAG),
- a partial frame (with VIDEO_BUF_FRAG),
- a last frame (with VIDEO_BUF_EOF),

The video devices that do not support fragmentation currently ignore
this flag.

As discussed in zephyrproject-rtos#66994 and zephyrproject-rtos#72827.

Co-authored-by: Lee <admin@arducam.com>
Co-authored-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
Signed-off-by: Josuah Demangeon <me@josuah.net>

include/zephyr/drivers/video.h

@@ -96,6 +96,14 @@ struct video_caps {
 	uint8_t min_vbuf_count;
 };
 
+/**
+ * @brief video_frame_fragmented_status enum
+ *
+ * Indicates the receiving status of fragmented frames.
+ */
+#define VIDEO_BUF_FRAG BIT(0)
+#define VIDEO_BUF_EOF  BIT(1)
+
 /**
  * @struct video_buffer
  * @brief Video buffer structure
@@ -116,6 +124,10 @@ struct video_buffer {
 	 * endpoints.
 	 */
 	uint32_t timestamp;
+	/** frame length for fragmented frames. */
+	uint32_t bytesframe;
+	/** receiving status for fragmented frames. */
+	uint32_t flags;
 };
 
 /**