libclang depends on ClangDriverOptions since r352803

Without this, the build would sometimes fail with

    In file included from clang/tools/libclang/CIndexer.cpp:17:
    In file included from clang/include/clang/Driver/Driver.h:15:
    clang/include/clang/Driver/Options.h:44:10: fatal error:
        'clang/Driver/Options.inc' file not found
    #include "clang/Driver/Options.inc"
             ^~~~~~~~~~~~~~~~~

if Options.inc wasn't generated before libclang was built
by coincidence.

(In the GN build, this works because lib/Driver there declares
the dep on tablegen as a public_dep since the generated file
is part of Driver's public interface, and then things work out
automatically without every client of Driver having to be careful.)

llvm-svn: 371205