As suggested, you can either use the upper 8 bits of your ADC result, and send it to the 8-bit PWM (mikroC's PWM library uses an 8-bit input). OR, manually use the PWM, (the datasheet provides step-by-step instructions for this) in which case you can use 10-bits to match the ADC.

For the simple case of using a pot to control PWM, using built-in libraries, using this line:

potdigital = ADC_READ(2) >> 2;

Your ADC result will be a 10-bit number (stored in unsigned int, 16-bit).

Left shift by 2 will knock this down to 8-bit by dumping the two LSB's (divide by 4).

At the moment, your ADC result is the equivalent of four 8-bit numbers, so the range of the pot (assuming its connected between GND and Vref/VDD) 0-100%, 0-100%, 0-100%, 0-100%.