[CodeGen] Fix warnings in sve-ld1-addressing-mode-reg-imm.ll

For the GetElementPtr case in function
  AddressingModeMatcher::matchOperationAddr
I've changed the code to use the TypeSize class instead of relying
upon the implicit conversion to a uint64_t. As part of this we now
check for scalable types and if we encounter one just bail out for
now as the subsequent optimisations doesn't currently support them.

This changes fixes up all warnings in the following tests:

  llvm/test/CodeGen/AArch64/sve-ld1-addressing-mode-reg-imm.ll
  llvm/test/CodeGen/AArch64/sve-st1-addressing-mode-reg-imm.ll

Differential Revision: https://reviews.llvm.org/D83124