Hi bud my phone stopped doing it after a week or so and I didn't do anything to stop it it just stopped asking so I've no answer for you, all I'd advise is if you have your phone to wipe itself after X amount of log in attempts I'd turn that feature off for now or you might find you take it out your pocket and it's gone and wiped itself clean. It's strange because there's nothing your likely to have in your pocket that even remotely resembles a finger unless of course you walk with your hand in your pocket and your inadvertantly putting your finger on your screen? I have my phone in my pocket but my phone screen is always pressed up against my leg I never have the phone facing outwards while in my pocket. Sorry I'm not much help but as I say it sorted itself out hopefully yours will do the same, mine did this pin request continuously for around 1 to 2 weeks then it stopped.
