Is SPU and SMPU instances for peripherals and memory same in ADSP-SC57x as it was in ADSP-SC58x processor?

No. The SPU and SMPU instances may not be same. So if you are porting any project written for ADSP-SC58x processor to ADSP-SC57x processor, then make sure that the SPU and SMPU instances are verified accordingly and changed if necessary.

The SPU and SMPU instance details will be available in the Hardware Reference Manual for ADSP-SC57x processor.

Thanks,