[clang] [llvm] [AArch64] Fix feature flags dependecies (PR #90612)

[Tomas Matheson via cfe-commits]

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@@ -1942,12 +1942,10 @@ def : RWSysReg<"PM",                0b11, 0b000, 0b0100, 0b0011, 0b001>;
 
 // 2023 ISA Extension
 // AArch64 Floating-point Mode Register controls behaviors of the FP8
-// instructions (FEAT_FPMR)
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tmatheson-arm wrote:

The comment `(FEAT_FPMR)` should stay, because it is still true even if we are not going to gate the registers by feature.

https://github.com/llvm/llvm-project/pull/90612