[mlir] Remove an unused local variable (NFC)#139351

kazutakahirata merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_001_tidy_bugprone-unused-local-non-trivial-variable_mlirkazutakahirata/llvm-project:cleanup_001_tidy_bugprone-unused-local-non-trivial-variable_mlirCopy head branch name to clipboard