Bug 13662: Enable GPRPair for all i64 operands of inline asm on ARM

This patch assigns paired GPRs  for inline asm with
64-bit data on ARM. It's enabled for both ARM and Thumb to support modifiers
like %H, %Q, %R.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185169 91177308-0d34-0410-b5e6-96231b3b80d8