[guide] Battery And Multitasking Improve For Miui

I noticed that the HELIO x20 is quite the power hungry chip so I dug around XDA MIUI devices forums for other devices and found out that Xiaomi MIUI roms use a service called 'perfservice' to control the CPU and can sometime be a hit and miss, so I did something;
STEP 1-this is for mediatek devices only
DISABLE PERFSERVICE and MY BATTERY LIFE HAS IMPROVED DRAMATICALLY.
What happens when perfservice is disabled is the cpu is controlled by MTK's cpu manager (not...​