kernel/process: Make Run's stack size parameter a u64

This will make operating with the process-related SVC commands much
nicer in the future (the parameter representing the stack size in
svcStartProcess is a 64-bit value).

src/core/hle/kernel/process.cpp

@@ -108,7 +108,7 @@ ResultCode Process::LoadFromMetadata(const FileSys::ProgramMetadata& metadata) {
     return handle_table.SetSize(capabilities.GetHandleTableSize());
 }
 
-void Process::Run(VAddr entry_point, s32 main_thread_priority, u32 stack_size) {
+void Process::Run(VAddr entry_point, s32 main_thread_priority, u64 stack_size) {
     // The kernel always ensures that the given stack size is page aligned.
     stack_size = Common::AlignUp(stack_size, Memory::PAGE_SIZE);
 

src/core/hle/kernel/process.h

@@ -210,7 +210,7 @@ public:
     /**
      * Applies address space changes and launches the process main thread.
      */
-    void Run(VAddr entry_point, s32 main_thread_priority, u32 stack_size);
+    void Run(VAddr entry_point, s32 main_thread_priority, u64 stack_size);
 
     /**
      * Prepares a process for termination by stopping all of its threads