DebugInfo: Remove unnecessary/mistaken inclusion of Bitcode/BitcodeAnalyzer.h

Introduced in r374582, Michael Spencer pointed out this broke the
modules build due to a missing tblgen dependency on
llvm/IR/Attributes.inc.

Michael fixed the dependency in r374827.

So this removes the inclusion and the new dependency (effectively
reverting r374827 and including the alternative fix of removing rather
than supporting the new dependency).

Thanks for the quick fix/notice, Michael!

llvm-svn: 374831