[X86] Arrange more CPU features to inherit from earlier CPUs. NFCI

This makes SandyBridge inherit back to Westmere/Nehalem.

Make bdver1-4 inherit from each other and btver2 inherit from btver1.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355935 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed