need way to upgrade touch controller firmware

I'm experiencing some rather annoying issues with taps not registering towards the edge of the screen after tapping towards the center of the screen first. This is on evergreen with touch controller firmware version 1.

@sebastian.krzyszkowiak mentioned in chat that this is a known issue, fixed by version 2. according to @martin.kepplinger (also in chat), there's vendor driver (not in this kernel, I presume) that allows fw upload, but the mainline driver does not.