[NEON] Fix combining of vldx_dup intrinsics with updating of base addresses

Resolves:
Unsupported ARM Neon intrinsics in Target-specific DAG combine
function for VLDDUP
https://bugs.llvm.org/show_bug.cgi?id=38031

Related diff: D48439

Differential Revision: https://reviews.llvm.org/D48920

llvm-svn: 336325