[RegBankSelect] Use RegisterBankInfo applyMapping method.

The RegBankSelect pass can now rely on the target to do the remapping of
the instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272169 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed