Avoid storing the Tcb pointer on the stack (#3819)

* Avoid storing the Tcb pointer on the stack

* Just return the already stored pointer in GetTcbBase

* Replace uses of GetTcbBase with g_curthread->tcb

* copyright 2025

* sir clang offnir, the all-formatting

src/core/tls.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #pragma once
@@ -36,9 +36,6 @@ u32 GetTcbKey();
 /// Sets the data pointer to the TCB block.
 void SetTcbBase(void* image_address);
 
-/// Retrieves Tcb structure for the calling thread.
-Tcb* GetTcbBase();
-
 /// Makes sure TLS is initialized for the thread before entering guest.
 void EnsureThreadInitialized();