kernel/thread: Make thread_id a 64-bit value

The kernel uses a 64-bit value for the thread ID, so we shouldn't be
using a 32-bit value.

src/core/gdbstub/gdbstub.cpp

@@ -201,11 +201,11 @@ void RegisterModule(std::string name, VAddr beg, VAddr end, bool add_elf_ext) {
     modules.push_back(std::move(module));
 }
 
-static Kernel::Thread* FindThreadById(int id) {
+static Kernel::Thread* FindThreadById(s64 id) {
     for (u32 core = 0; core < Core::NUM_CPU_CORES; core++) {
         const auto& threads = Core::System::GetInstance().Scheduler(core).GetThreadList();
         for (auto& thread : threads) {
-            if (thread->GetThreadID() == static_cast<u32>(id)) {
+            if (thread->GetThreadID() == static_cast<u64>(id)) {
                 current_core = core;
                 return thread.get();
             }

src/core/hle/kernel/kernel.cpp

@@ -156,7 +156,7 @@ struct KernelCore::Impl {
     // TODO(Subv): Start the process ids from 10 for now, as lower PIDs are
     // reserved for low-level services
     std::atomic<u64> next_process_id{10};
-    std::atomic<u32> next_thread_id{1};
+    std::atomic<u64> next_thread_id{1};
 
     // Lists all processes that exist in the current session.
     std::vector<SharedPtr<Process>> process_list;
@@ -242,7 +242,7 @@ u32 KernelCore::CreateNewObjectID() {
     return impl->next_object_id++;
 }
 
-u32 KernelCore::CreateNewThreadID() {
+u64 KernelCore::CreateNewThreadID() {
     return impl->next_thread_id++;
 }
 

src/core/hle/kernel/kernel.h

@@ -91,7 +91,7 @@ private:
     u64 CreateNewProcessID();
 
     /// Creates a new thread ID, incrementing the internal thread ID counter.
-    u32 CreateNewThreadID();
+    u64 CreateNewThreadID();
 
     /// Creates a timer callback handle for the given timer.
     ResultVal<Handle> CreateTimerCallbackHandle(const SharedPtr<Timer>& timer);

src/core/hle/kernel/thread.h

@@ -151,7 +151,7 @@ public:
      * Gets the thread's thread ID
      * @return The thread's ID
      */
-    u32 GetThreadID() const {
+    u64 GetThreadID() const {
         return thread_id;
     }
 
@@ -379,7 +379,7 @@ private:
 
     Core::ARM_Interface::ThreadContext context{};
 
-    u32 thread_id = 0;
+    u64 thread_id = 0;
 
     ThreadStatus status = ThreadStatus::Dormant;