[llvm] [clang] [RISCV] Add support for Smepmp 1.0 (PR #78489)

[Min-Yih Hsu via cfe-commits]

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@@ -716,6 +716,13 @@ def FeatureStdExtSmaia
                        "AIA specifies for a hart, over all privilege levels.)",
                        []>;
 
+def FeatureStdExtSmepmp
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mshockwave wrote:

> Can we keep smaia and ssaia together since they come from the same specification? I assume you were alphabetizing, but I don't think there's any order in this file.

I've reordered it here and other places for consistency.

https://github.com/llvm/llvm-project/pull/78489