libcamera: Add ClockRecovery class to generate wallclock timestamps

The ClockRecovery class takes pairs of timestamps from two different
clocks, and models the second ("output") clock from the first ("input")
clock.

We can use it, in particular, to get a good wallclock estimate for a
frame's SensorTimestamp.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -21,6 +21,7 @@ libcamera_internal_sources = files([
     'byte_stream_buffer.cpp',
     'camera_controls.cpp',
     'camera_lens.cpp',
+    'clock_recovery.cpp',
     'control_serializer.cpp',
     'control_validator.cpp',
     'converter.cpp',