How to build videodev as an external module on Xavier?

During installation of librealsense on Xavier (L4T 31-1-0) videodev.ko kernel module needs to be patched and built as an external module.
But only videobuf-core.ko and videobuf-vmalloc.ko are built after issuing
make -C $KBASE M=$KBASE/drivers/media/v4l2-core modules

I’ve tried to set CONFIG_VIDEO_DEV and CONFIG_VIDEO_V4L2 to “m” instead of “y”,
but with no luck - they have been reverted to “y” after “make oldconfig”.
What am I doing wrong? Thanks.

We suggest you go to

Users there should be more experienced in realsense USB cams.

Well, thanks, for sure I’ve asked and looked for my problem there, but with no luck yet.
That is why I’m asking here.
And my question concerns not Realsense but more how to build videodev as an external module.
Realsense part is just a background.