Keep SPI active on LPC176x (#19932)

Marlin/src/HAL/LPC1768/HAL_SPI.cpp

 }
 
 void SPIClass::end() {
-  // SSP_Cmd(_currentSetting->spi_d, DISABLE);  // stop device or SSP_DeInit?
-  SSP_DeInit(_currentSetting->spi_d);
+  // Neither is needed for Marlin
+  //SSP_Cmd(_currentSetting->spi_d, DISABLE);
+  //SSP_DeInit(_currentSetting->spi_d);
 }
 
 void SPIClass::send(uint8_t data) {