LSR: Don't drop address space when type doesn't match

For targets with different addressing modes in each address space,
if this is dropped querying isLegalAddressingMode later with this
will give a nonsense result, breaking the isLegalUse assertions.

This is a candidate for the 4.0 release branch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293542 91177308-0d34-0410-b5e6-96231b3b80d8