[RISCV] Fix comment about what version of Zvk* we support. NFC

[craig.topper]

Summary

As far as I know we support 0.5.1.

[asb]

LGTM. Now we list the versions in RISCVUsage as well as RISCVISAInfo, perhaps it's a bit redundant listing the version in the .td file (I've been tending not to in recent patches for new extensions).

llvm/lib/Target/RISCV/RISCVInstrInfoZvk.td

 //===-- RISCVInstrInfoZvk.td - RISC-V 'Zvk' instructions -------*- tablegen -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file describes the RISC-V instructions from the standard 'Zvk',
-// Vector Cryptography Instructions extension, version 0.3.
+// Vector Cryptography Instructions extension, version 0.5.1.
 //
 //===----------------------------------------------------------------------===//
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in {
 multiclass VCLMUL_MV_V_X<string opcodestr, bits<6> funct6> {
   def V  : VALUVV<funct6, OPMVV, opcodestr # "." # "vv">,
            Sched<[WriteVIALUV_WorstCase, ReadVIALUV_WorstCase,
                   ReadVIALUV_WorstCase, ReadVMask]>;