properly set test pattern to a sub-device

[Petko Manolov <petko.manolov@xxxxxxxxxxxx>]

	Hi guys,

I've got a long pipeline of four entities and need to make the imx492 sensor 
stream out a test pattern.  When i do:

	v4l2-ctl -d /dev/v4l-subdev2 --set-ctrl=test_pattern=2

I can see the driver acknowledging the switch to test pattern 2.  However, when 
start streaming with:

	v4l2-ctl -d /dev/video0 --stream-mmap --stream-to=frame.raw --stream-count=1

the driver reports setting the test pattern to the default 0.  How should this 
be done properly?


thanks,
Petko