Add beginTransaction to HAL SPI (#9019)

Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp

@@ -164,6 +164,13 @@ void spiSendBlock(uint8_t token, const uint8_t* buf) {
   SPI.endTransaction();
 }
 
+/** Begin SPI transaction, set clock, bit order, data mode */
+void spiBeginTransaction(uint32_t spiClock, uint8_t bitOrder, uint8_t dataMode) {
+  spiConfig = SPISettings(spiClock, bitOrder, dataMode);
+  
+  SPI.beginTransaction(spiConfig);
+}    
+
 #endif // SOFTWARE_SPI
 
 #endif // __STM32F1__