Add /usr/lib/aarch64-linux-gnu directory to search for the unixODBC library

[DmitriyKarpovskiy1]

Changes required to create an ODBC connector for the aarch64 architecture.

[lawrinn]

Thank you for your pull request! In order to accept it, we need you write in the comment, that you are contributing your new code of the whole pull request, including one or several files that are either new files or modified ones, under the BSD-new license.
Not sure if that is also required for cmake config changes, but I'd prefer to stay on the safe side

[lawrinn]

Actually, in the last commit I've added CMAKE_LIBRARY_ARCHITECTURE to the list of searched library suffixes and /usr/lib/${CMAKE_LIBRARY_ARCHITECTURE} directly to list of libraries to search. If I understand correctly that should do what you need, but I cannot check if it really does.

[lawrinn]

I think /usr/lib/${CMAKE_LIBRARY_ARCHITECTURE} should do the job, and I can close this pull request.
If it does not, then please re-open the PR.