[ARM GlobalISel] Style fix. NFCI

Add the opcode for ADDrr / t2ADDrr to the Opcode cache, as we did for
all other opcodes where the handling is otherwise the same between arm
mode and thumb2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354115 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed