[ELF] - Ignore R_386_NONE.

We had an error when met this relocation
after latest changes aboult listing
x86 relocations explicitly.

Since we support R_X86_64_NONE,
and GNU ld supports R_386_NONE,
it seems reasonable to have.

Differential revision: https://reviews.llvm.org/D28552

llvm-svn: 291672