[MLIR][LLVM] Fix import of dso_local attribute (#124822)
The import of LLVM IR should use is isDSOLocal instead of
hasLocalLinkage to set the dso_local attribute.
Without this change, function definitions that mostly have external
linkage would be missing dso_local attribute during translation.
---------
Co-authored-by: Tobias Gysi <tobias.gysi@nextsilicon.com>
