Most dark wood veneer paneling that I have met is stained and unsealed, and if you try to rub paint into it for a whitewashed look, the original dark stain will bleed into your whitewash and look horrible. Best look for this is probably two coats of a good stain blocker/primer, followed by a top coat. The first coat of primer will take forever to brush and roll on because it will be ****ed up by the paneling, but persevere, it gets better. If you don't want to keep the solid color look, experiment with adding texture to the 'boards' with decorative paint techniques like colorwashing. Colorwashing is just thinning paint with glaze(easier, dries more slowly) or water (dries FAST) and applying with a brush or rags. You can paint a practice board when you do the walls and try it out risk free.

If your paneling is sealed, like it looks glossy and varnished, you might have enough wood grain texture to whitewash the paneling. Or it might be too smooth to catch the paint and give you the look you want. But if it is sealed, you can try some thinned white paint in an inconspicuous spot, see if you like it then wipe it off before it dries.

Another option is to chat with the salespeople at a real paint store and see what they say. New products are arriving every day, and they would also know old solutions. I have also had luck at my local big box DIY by visiting on a Tuesday morning and looking for the real handymen for help.

Sorry this is so long, I am just sympathetic because we painted the dark paneled walls in our family room. It looks tons better, but it looks like painted paneling and isn't what I really want. There is always drywall!