[HIP] Remove useless sections in linked files

clang-offload-bundler creates __CLANG_OFFLOAD_BUNDLE__* sections in the bundles,
which get into the linked files. These sections are useless after linking. They waste disk
space and cause confusion for clang when directly linked with other object files, therefore
should be removed.

Differential Revision: https://reviews.llvm.org/D54275

llvm-svn: 346536