Misc implementations and fixes. (#250)

* Implement `sceKernelFtruncate` and `sceKernelUnlink`.

* Remove unused variable.

* Implement `sceKernelReserveVirtualRange`, misc fixes

* Fix `sceKernelReserveVirtualRange`.

* Add TODO on reserve

* Replace comment with assert.

* Add missing copyright header

* Add `UNREACHABLE` for `IOFile::Unlink`.

* Move NT API initialization out of the header

* Fix bug where files were always mapped as read only.

* `clang-format`

src/common/ntapi.cpp

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "ntapi.h"
+
+NtDelayExecution_t NtDelayExecution = nullptr;
+NtSetInformationFile_t NtSetInformationFile = nullptr;
+
+namespace Common::NtApi {
+
+void Initialize() {
+    HMODULE nt_handle = GetModuleHandleA("ntdll.dll");
+
+    // http://stackoverflow.com/a/31411628/4725495
+    NtDelayExecution = (NtDelayExecution_t)GetProcAddress(nt_handle, "NtDelayExecution");
+    NtSetInformationFile =
+        (NtSetInformationFile_t)GetProcAddress(nt_handle, "NtSetInformationFile");
+}
+
+} // namespace Common::NtApi