kernel/process: Start the main thread using the specified ideal core

This matches kernel behavior in that processes are started using their
specified ideal core, rather than always starting on core 0.

src/core/hle/kernel/process.cpp

@@ -35,8 +35,8 @@ void SetupMainThread(Process& owner_process, KernelCore& kernel, VAddr entry_poi
 
     // Initialize new "main" thread
     const VAddr stack_top = owner_process.VMManager().GetTLSIORegionEndAddress();
-    auto thread_res = Thread::Create(kernel, "main", entry_point, priority, 0, THREADPROCESSORID_0,
-                                     stack_top, owner_process);
+    auto thread_res = Thread::Create(kernel, "main", entry_point, priority, 0,
+                                     owner_process.GetIdealCore(), stack_top, owner_process);
 
     SharedPtr<Thread> thread = std::move(thread_res).Unwrap();