[X86] Drop the 64-bit alignment for LOW32_ADDR_ACCESS register class.

The only 64-bit register in that register class is RIP and it will not
get spilled in the current ABIs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268963 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed