Refact ARM Thumb1 tMOVr instruction family.

Refact ARM Thumb1 tMOVr instruction family.

Merge the tMOVr, tMOVgpr2tgpr, tMOVtgpr2gpr, and tMOVgpr2gpr instructions
into tMOVr. There's no need to keep them separate. Giving the tMOVr
instruction the proper GPR register class for its operands is sufficient
to give the register allocator enough information to do the right thing
directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134204 91177308-0d34-0410-b5e6-96231b3b80d8