feat: some clean up and validation of multiboot header

kernel/libk/kprint.c

@@ -50,6 +50,10 @@ void kprint_internal(const char *msg) {
     }
 }
 
+void kprint_sync(const char* msg) {
+    kprint_internal(msg);
+}
+
 void kprint_init() {
     kprint_stream = stream_create(STREAM_SIZE);
 }