SPI and pins cleanup

Marlin/src/HAL/DUE/dogm/u8g_com_HAL_DUE_shared_hw_spi.cpp

@@ -64,12 +64,11 @@
 
 #include "../../../MarlinCore.h"
 
-void spiBegin();
-void spiInit(uint8_t spiRate);
-void spiSend(uint8_t b);
-void spiSend(const uint8_t* buf, size_t n);
+#ifndef LCD_SPI_SPEED
+  #define LCD_SPI_SPEED SPI_QUARTER_SPEED
+#endif
 
-#include "../../shared/Marduino.h"
+#include "../../shared/HAL_SPI.h"
 #include "../fastio.h"
 
 void u8g_SetPIOutput_DUE_hw_spi(u8g_t *u8g, uint8_t pin_index) {
@@ -100,11 +99,7 @@ uint8_t u8g_com_HAL_DUE_shared_hw_spi_fn(u8g_t *u8g, uint8_t msg, uint8_t arg_va
 
       spiBegin();
 
-      #ifndef SPI_SPEED
-        #define SPI_SPEED SPI_FULL_SPEED  // use same SPI speed as SD card
-      #endif
-      spiInit(2);
-
+      spiInit(LCD_SPI_SPEED);
       break;
 
     case U8G_COM_MSG_ADDRESS:                     /* define cmd (arg_val = 0) or data mode (arg_val = 1) */

Marlin/src/HAL/DUE/dogm/u8g_com_HAL_DUE_sw_spi.cpp

@@ -59,9 +59,6 @@
 
 #if HAS_MARLINUI_U8GLIB && DISABLED(U8GLIB_ST7920)
 
-#undef SPI_SPEED
-#define SPI_SPEED 2  // About 2 MHz
-
 #include "u8g_com_HAL_DUE_sw_spi_shared.h"
 
 #include "../../shared/Marduino.h"