elfutils: Add three files to the compile list

The following three files are needed to compile perf-3.17. They were in
the source directory but not in the compile list.

  libelf/elf32_updatefile.c
  libelf/elf64_updatefile.c
  libdw/dwarf_getcfi_elf.c

Change-Id: I6c6ec25efd90e3e66600c37e104dcea929484d65
Merge "elfutils: Add three files to the compile list"