[AsmParser][TableGen] Add VariantID argument to the generated mnemonic spell check...

[AsmParser][TableGen] Add VariantID argument to the generated mnemonic spell check function so it can use the correct table based on variant.

I'm considering implementing the mnemonic spell checker for x86, and that would require the separate intel and att variants.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316641 91177308-0d34-0410-b5e6-96231b3b80d8