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);
 }

kernel/libk/kprint.h

@@ -15,6 +15,8 @@ void kprint_register(kprint_handler);
 
 void kprint(const char *msg);
 
+void kprint_sync(const char* msg);
+
 void kprint_init();
 
 void kprint_start_task();

kernel/libk/libk.c

@@ -17,12 +17,12 @@ void k_wait_for_interrupt() {
 
 void noreturn k_panics(const char *msg) {
     // todo this is not printed
-    kprint(msg);
+    kprint_sync(msg);
     k_panic();
 }
 
 void noreturn k_panic() {
-    kprint("PANIC!");
+    kprint_sync("PANIC!");
     while (true) {
         __asm__ __volatile__("cli;"
                              "hlt;");