Remove the now redundant FeatureFP16 from the Cortex-A15 feature list. It was made redundant when FeatureVFP4 was added which implies FP16.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187985 91177308-0d34-0410-b5e6-96231b3b80d8