pipeline: ipa: raspberrypi: Handle any externally allocated FrameBuffer

Handle the case where a FrameBuffer that has been externally allocated
(i.e. not through the v4l2 video device) is passed into a Request.

We must store the buffer pointer in the stream internal buffer list to
identify when used.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

include/libcamera/ipa/raspberrypi.h

@@ -28,11 +28,12 @@ enum RPiOperations {
 	RPI_IPA_EVENT_QUEUE_REQUEST,
 };
 
-enum RPiIpaMask {
-	ID		= 0x0ffff,
-	STATS		= 0x10000,
-	EMBEDDED_DATA	= 0x20000,
-	BAYER_DATA	= 0x40000
+enum RPiBufferMask {
+	ID		= 0x00ffff,
+	STATS		= 0x010000,
+	EMBEDDED_DATA	= 0x020000,
+	BAYER_DATA	= 0x040000,
+	EXTERNAL_BUFFER	= 0x100000,
 };
 
 /* Size of the LS grid allocation. */