[clang] [llvm] [AArch64] set AppleA14 architecture version to v8.4-a (PR #92600)

[Ahmed Bougacha via llvm-commits]

================
@@ -718,12 +718,16 @@ def ProcessorFeatures {
   list<SubtargetFeature> AppleA13 = [HasV8_4aOps, FeatureCrypto, FeatureFPARMv8,
                                      FeatureNEON, FeaturePerfMon, FeatureFullFP16,
                                      FeatureFP16FML, FeatureSHA3];
+  // Apple A14 and M1 chips are based on Armv8.5-a but without BTI. Since there
----------------
ahmedbougacha wrote:

Well, on the flipside, having one specific quirk called out somewhere and no other quirk called out elsewhere would only instill misplaced confidence in anyone who would want to update these cpu definitions.

https://github.com/llvm/llvm-project/pull/92600