[clang] [Clang] NFC Silence compiler warning spam (PR #86532)

[via cfe-commits]

https://github.com/NagyDonat created https://github.com/llvm/llvm-project/pull/86532

This non-functional change eliminates the compiler warning
```
/repo/llvm-project/clang/include/clang/Basic/SyncScope.h: In member function ‘virtual bool clang::AtomicScopeGenericModel::isValid(unsigned int) const’:
/repo/llvm-project/clang/include/clang/Basic/SyncScope.h:255:14: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
     return S >= static_cast<unsigned>(System) &&
            ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
which was appearing repeatedly, as this header was included into very many source files (through chains of 6-7 header files).

>From 5177df2ed3ce068264885a12c85a5fb9aaa464a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Don=C3=A1t=20Nagy?= <donat.nagy at ericsson.com>
Date: Mon, 25 Mar 2024 17:53:02 +0100
Subject: [PATCH] [Clang] NFC Silence compiler warning spam
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This non-functional change eliminates the compiler warning
/repo/llvm-project/clang/include/clang/Basic/SyncScope.h: In member function ‘virtual bool clang::AtomicS
copeGenericModel::isValid(unsigned int) const’:
/repo/llvm-project/clang/include/clang/Basic/SyncScope.h:255:14: warning: comparison of unsigned expressi
on >= 0 is always true [-Wtype-limits]
     return S >= static_cast<unsigned>(System) &&
            ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
which was appearing repeatedly, as this header was included into very
many source files (through chains of 6-7 header files).
---
 clang/include/clang/Basic/SyncScope.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/clang/include/clang/Basic/SyncScope.h b/clang/include/clang/Basic/SyncScope.h
index bc7ec7b5cf777e..45beff41afa11d 100644
--- a/clang/include/clang/Basic/SyncScope.h
+++ b/clang/include/clang/Basic/SyncScope.h
@@ -252,8 +252,7 @@ class AtomicScopeGenericModel : public AtomicScopeModel {
   }
 
   bool isValid(unsigned S) const override {
-    return S >= static_cast<unsigned>(System) &&
-           S <= static_cast<unsigned>(Last);
+    return S <= static_cast<unsigned>(Last);
   }
 
   ArrayRef<unsigned> getRuntimeValues() const override {