cppcheck: misra-c2012-11.6

Avoid casting between pointer to void and an arithmetic type.
Refactor bootloader address handling for easier understanding.

board/early_init.h

@@ -6,10 +6,17 @@
 extern void *g_pfnVectors;
 extern uint32_t enter_bootloader_mode;
 
+typedef void (*bootloader_fcn)(void);
+typedef bootloader_fcn *bootloader_fcn_ptr;
+
 void jump_to_bootloader(void) {
   // do enter bootloader
   enter_bootloader_mode = 0;
-  void (*bootloader)(void) = (void (*)(void)) (*((uint32_t *)BOOTLOADER_ADDRESS));
+
+  // retrieve bootloader function pointer that is stored at BOOTLOADER_ADDRESS
+  bootloader_fcn_ptr bootloader_ptr = (bootloader_fcn_ptr)BOOTLOADER_ADDRESS;
+  // retrieve actual function address from bootloader pointer
+  bootloader_fcn bootloader = *bootloader_ptr;
 
   // jump to bootloader
   enable_interrupts();