[cpu-detection] Add missing break statements in outer switches

Summary:
Break on all switch cases for outer and inner switches.
No functionality changed.

Reviewers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D21158

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272228 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed