Yesterday it seemed like my note cured itself, the l2_hsic wakelock was up for about 10 minutes and after 19 hrs I had 45% left. Without changing anything today it is worse like before. The Samsung-Support did not know what to do except for a factory reset, but I'd really like to find a better solution.
It seems like a restart cures the wakelock for about 24 hrs. I restarted it 1 hour ago and until now the l2_hsic hasn't come up...