Merge pull request #1281 from Grogyan/patch-2

MAX6675 Slave Select pin

Marlin/pins.h

   #define SCK_PIN          52
   #define MISO_PIN         50
   #define MOSI_PIN         51
-  #define MAX6675_SS       53
+  #define MAX6675_SS       66// Do not use pin 53 if there is even the remote possibility of using Dsplay/SD card
 #else
-  #define MAX6675_SS       49
+  #define MAX6675_SS       66// Do not use pin 49 as this is tied to the switch inside the SD card socket to detect if there is an SD card present
 #endif
 
 #endif // RAMPS_OLD || RAMPS_13_EFB || RAMPS_13_EEB || RAMPS_13_EFF || 3DRAG