feat: make kernel architecture-agnostic; primitive work on arm port

kernel/src/Drivers/USB/Bluetooth/L2cap.cpp

@@ -5,6 +5,7 @@
 */
 
 #include "L2cap.hpp"
+#include <Arch/Cpu.hpp>
 #include "Hci.hpp"
 #include "A2dp.hpp"
 #include "Avrcp.hpp"
@@ -12,7 +13,7 @@
 #include <Terminal/Terminal.hpp>
 #include <CppLib/Stream.hpp>
 #include <Libraries/Memory.hpp>
-#include <Timekeeping/ApicTimer.hpp>
+#include <Timekeeping/Timer.hpp>
 
 using namespace Kt;
 
@@ -554,7 +555,7 @@ namespace Drivers::USB::Bluetooth::L2cap {
             if (ch && ch->Configured) return true;
 
             for (int j = 0; j < 100; j++) {
-                asm volatile("" ::: "memory");
+                Arch::CompilerBarrier();
             }
         }
         return false;