Fix llvm-gcc build for armv6t2 and later architectures. The hasV6T2Ops

Fix llvm-gcc build for armv6t2 and later architectures.  The hasV6T2Ops
predicate does not check if Thumb mode is enabled, and when in ARM mode
there are still some checks for constant-pool use that need to run.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73887 91177308-0d34-0410-b5e6-96231b3b80d8