Bugfix SS pin definitions

[Hasi123]

Strangely the old code worked on some boards, but not on others. Found this little bug and thought I would create a pull request.

[prunkdump]

Hi Hasi !

Does you understand how to identify the different board type ?

You talk about Pro-Mini only ?

[Hasi123]

Well you already defined B0 in the code, and for that the port register is PORTB and the ddr is DDRB.

#ifndef SD_SS_PORT
#define SD_SS_PORT B
#endif
/* !!! default changed !!! */
#ifndef SD_SS_PIN
#define SD_SS_PIN 0
#endif

I do not understand your question, the SD SS pin is not board dependent, but can be freely chosen depending on where you connect the SS pin of the SD card.