I'm afraid you have to find it out by yourself. I cant help you, besause I have Mi Max. Disassembling Redmi Note is not very difficult, YT is full of "how to" videos.
My Mi MAX (hydrogen) lost the fingerprint option. Even in the settings there is no option to turn on fingerprint scanner.
I made google search and found that there are couple of threads in miui official forum, but no solution.
Any ideas???