Patch for "FIXME: only blink at top when going up, not down"

[Niku Toivola]

Creating a separate issue in case you missed my proposed patch for the annoying blink while ramping down from turbo in https://bugs.launchpad.net/flashlight-firmware/+bug/2040058/comments/2. I believe the attached simple patch fixes it, at least it seems to work without issue on my lights and in my configuration.

[Niku Toivola (niku-toivola)]

The initial step down from turbo is still a bit abrupt with this, but at least it doesn't blink. Making it use smooth steps did not seem trivial.