[llvm-debuginfo-analyzer] (08/09) - ELF Reader

The fix for the unitest case introduced a dependency on the
MC library causing a failure in:

  https://lab.llvm.org/buildbot/#/builders/121/builds/24567
  clang-ppc64le-multistage/stage1
  undefined reference to symbol 'llvm::TargetRegistry::lookupTarget'

Added:
- MC to the LLVM_LINK_COMPONENTS list.

Reviewed By: jryans

Differential Revision: https://reviews.llvm.org/D136837