pm: Use result definitions instead of magic numbers

stratosphere/pm/source/pm_shell.cpp

@@ -34,7 +34,7 @@ Result ShellService::TerminateProcessId(u64 pid) {
     if (proc != nullptr) {
         return svcTerminateProcess(proc->handle);
     } else {
-        return 0x20F;
+        return ResultPmProcessNotFound;
     }
 }
 
@@ -45,7 +45,7 @@ Result ShellService::TerminateTitleId(u64 tid) {
     if (proc != NULL) {
         return svcTerminateProcess(proc->handle);
     } else {
-        return 0x20F;
+        return ResultPmProcessNotFound;
     }
 }
 
@@ -62,9 +62,9 @@ Result ShellService::FinalizeExitedProcess(u64 pid) {
     
     auto proc = Registration::GetProcess(pid);
     if (proc == NULL) {
-        return 0x20F;
+        return ResultPmProcessNotFound;
     } else if (proc->state != ProcessState_Exited) {
-        return 0x60F;
+        return ResultPmNotExited;
     } else {
         Registration::FinalizeExitedProcess(proc);
         return 0x0;
@@ -79,7 +79,7 @@ Result ShellService::ClearProcessNotificationFlag(u64 pid) {
         proc->flags &= ~PROCESSFLAGS_CRASHED;
         return 0x0;
     } else {
-        return 0x20F;
+        return ResultPmProcessNotFound;
     }
 }
 
@@ -98,7 +98,7 @@ Result ShellService::GetApplicationProcessId(Out<u64> pid) {
         pid.SetValue(app_proc->pid);
         return 0;
     }
-    return 0x20F;
+    return ResultPmProcessNotFound;
 }
 
 Result ShellService::BoostSystemMemoryResourceLimit(u64 sysmem_size) {