[clang] [Clang] Refactor diagnostics for SME builtins. (PR #78258)

[Sander de Smalen via cfe-commits]

================
@@ -3005,6 +3005,15 @@ enum ArmStreamingType {
   ArmStreamingOrSVE2p1
 };
 
+enum ArmSMEState : unsigned {
+  ArmNoState = 0,
+
+  ArmInZA = 0b01,
+  ArmOutZA = 0b10,
+  ArmInOutZA = 0b11,
+  ArmZAMask = 0b11,
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sdesmalen-arm wrote:

I'm not really convinced that's better because they're two different things. One is an enum value for the state of ZA, and the other is a bitmask. If we'd want to change the encoding of the ZA attributes, we don't necessarily have to update the mask.

https://github.com/llvm/llvm-project/pull/78258