Alright guys here it is. LightXT its pretty self explanatory. This does require you to be rooted. This is V.1 so there might be bugs but I haven't found any so you should be fine. This has only been tested on US XT720 running Khalpowers miui themed V3 but technically it should work on all models of this phone with the auto focus led.
Disclaimer: I am not held responsible for any harm this app may cause your phone or your LED light.
If you like this App please dont forget to hit the thanks button.
*****THIS APP DOES NOT TURN YOUR XENON FLASH ON IT TURNS ON YOUR AUTO FOCUS LIGHT***** sorry for the confusion