Move kboot related code to shared/kboot.[ch] because it'll be reused by the firmwares of the add-ons.

shared/kboot.c

@@ -0,0 +1,12 @@
+#include "kboot.h"
+
+void JumpToKboot(void) {
+    uint32_t runBootloaderAddress;
+    void (*runBootloader)(void *arg);
+
+    // Read the function address from the ROM API tree.
+    runBootloaderAddress = **(uint32_t **)(0x1c00001c);
+    runBootloader = (void (*)(void * arg))runBootloaderAddress;
+
+    runBootloader(NULL);
+}