Update InterruptVectors_Due.cpp

const pfnISR_Handler *isrtab = get_relocated_table_addr();

What compiler do you use? Arduino 1.8.5 can't compile this "const".

Marlin/src/HAL/HAL_DUE/InterruptVectors_Due.cpp

@@ -74,7 +74,7 @@ static pfnISR_Handler* get_relocated_table_addr(void) {
 
 pfnISR_Handler install_isr(IRQn_Type irq, pfnISR_Handler newHandler) {
   // Get the address of the relocated table
-  const pfnISR_Handler *isrtab = get_relocated_table_addr();
+  pfnISR_Handler *isrtab = get_relocated_table_addr();
 
   // Disable global interrupts
   CRITICAL_SECTION_START;