🍻 Preliminary fix for Max31865 SPI (#22682)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/libs/MAX31865.h

@@ -90,6 +90,13 @@ private:
   static SPISettings spiConfig;
 
   TERN(LARGE_PINMAP, uint32_t, uint8_t) _sclk, _miso, _mosi, _cs;
+
+  #ifdef TARGET_LPC1768
+    uint8_t _spi_speed;
+  #else
+    uint16_t _spi_delay;
+  #endif
+
   float Rzero, Rref;
 
   void setConfig(uint8_t config, bool enable);
@@ -99,7 +106,9 @@ private:
   uint16_t readRegister16(uint8_t addr);
 
   void writeRegister8(uint8_t addr, uint8_t reg);
-  uint8_t spixfer(uint8_t addr);
+  uint8_t spiTransfer(uint8_t addr);
+
+  void softSpiBegin(const uint8_t spi_speed);
 
 public:
   #ifdef LARGE_PINMAP