[ORC] Add BitReader/BitWriter to target_link_libraries
[ORC] Add BitReader/BitWriter to target_link_libraries

Summary:
CompileOnDemandLayer.cpp uses function in these libraries, and builds
with `-DSHARED_LIB=ON` fail without this.

Reviewers: lhames

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D48995

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@336389 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm