[X86][compiler-rt] Add additional CPUs and features to the cpu detection to match libgcc

Summary: This patch adds additional features and cpus from libgcc. Unfortunately we've overflowed the existing 32-bits of features so we had to add a new __cpu_features2 variable to hold the additional bits. This matches libgcc as far as I can tell.

Reviewers: echristo

Reviewed By: echristo

Subscribers: dberris, llvm-commits

Differential Revision: https://reviews.llvm.org/D53461

llvm-svn: 344830