Suppress some clang-tidy errors

Split the .clang-tidy check lists out over multiple lines to improve
readability.

Suppress `misc-non-private-member-variables-in-classes` as the code
currently contains many instances that fail this check.

Drop `constexpr` from `LoopControlLoopCountINTELMask` after clang
started diagnosing this with b364535 ("[Clang] Diagnose
ill-formed constant expression when setting ...", 2022-07-28).
Removing `constexpr` is just a workaround, the long term fix would be
to upstream the new enum value to `spirv.hpp`.

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@c5b29f2

Author: svenvh

.clang-tidy

@@ -1,4 +1,21 @@
-Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-misc-no-recursion,readability-identifier-naming'
+Checks: |
+  -*,
+  clang-diagnostic-*,
+  llvm-*,
+  -llvm-header-guard,
+  misc-*,
+  -misc-no-recursion,
+  -misc-non-private-member-variables-in-classes,
+  -misc-unused-parameters,
+  readability-identifier-naming
+WarningsAsErrors: |
+  llvm-*,
+  -llvm-header-guard,
+  misc-*,
+  -misc-no-recursion,
+  -misc-non-private-member-variables-in-classes,
+  -misc-unused-parameters,
+  readability-identifier-naming
 CheckOptions:
   - key:             readability-identifier-naming.ClassCase
     value:           CamelCase
@@ -24,3 +41,5 @@ CheckOptions:
     value:           1
   - key:             modernize-use-default-member-init.UseAssignment
     value:           1
+  - key:             llvm-namespace-comment.ShortNamespaceLines
+    value:           '25'

llvm-spirv/lib/SPIRV/libSPIRV/spirv_internal.hpp

@@ -184,7 +184,7 @@ constexpr ExecutionMode ExecutionModeFastCompositeKernelINTEL =
 constexpr ExecutionMode ExecutionModeStreamingInterfaceINTEL =
     static_cast<ExecutionMode>(IExecModeStreamingInterfaceINTEL);
 
-constexpr LoopControlMask LoopControlLoopCountINTELMask =
+static const LoopControlMask LoopControlLoopCountINTELMask =
     static_cast<LoopControlMask>(ILoopControlLoopCountINTELMask);
 
 } // namespace internal