Using Internal Oscillator
Just change this config option to select the Fast RC oscillator instead of PRIPLL.
#pragma config FNOSC = FRCPLL // Oscillator Selection Bits (Fast RC Osc w/PLL)
The Fast RC oscillator is 8MHz so same other setup as using an 8MHz crystal, apart from the accuracy not being as good.
The POSCMOD setting is supposed to have no effect when FRC is selected – its value is don't care. However we have found on some devices that if it is not set to off as below then the RA2 and RA3 pins often shared with the OSC1 and OSC2 pins won't work as IO:
#pragma config POSCMOD = OFF