Make GlobalISel depend on SelectionDAG after D63169

GlobalISel/IRTranslator.cpp now references SelectionDAG/FunctionLoweringInfo.cpp.
This fixes a link error in -DBUILD_SHARED_LIBS=on builds:

    ld.lld: error: undefined symbol: llvm::FunctionLoweringInfo::clear()
    >>> referenced by IRTranslator.cpp:2198 (../lib/CodeGen/GlobalISel/IRTranslator.cpp:2198)
    >>>               lib/CodeGen/GlobalISel/CMakeFiles/LLVMGlobalISel.dir/IRTranslator.cpp.o:(llvm::IRTranslator::finalizeFunction())

llvm-svn: 364124