Sorry I'm a bit late (5 years late) but hopefully this can help someone who's just now trying to do this!
There's an old obscure Sunfounder library, "rfid1.h" that lets you declare every pin. Like this:
It's a bit hard to find the library online these days, but at the bottom of this page (http://wiki.sunfounder.cc/index.php?title=Mifare_RC522_Module_RFID_Reader) if you download the "RFID-RC522_test_experiment" zip file it will have the library in there. The secret is that this library includes a software SPI which is sort of like a software serial for SPI communication. Letting other digital pins be used as MISO etc...
This library also makes it much easier to use multiple RFIDs reliably since they don't have to share all the same pins.
You can find some example code here: https://www.sunfounder.com/learn/RFID_kit_V1_for_Arduino/lesson-29-rfid-entrance-guard-system-rfid-kit-v1-0-for-arduino.html