Add beginTransaction to HAL SPI (#9019)

Marlin/src/HAL/HAL_TEENSY35_36/HAL_spi_Teensy.cpp

@@ -101,4 +101,12 @@ void spiSendBlock(uint8_t token, const uint8_t* buf) {
 }
 
 
+/** 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