[clang] [AArch64] Fix GNU ILP32 frontend data model (PR #225939)

[Peter Smith via cfe-commits]

smithp35 wrote:

ILP32 support has been deprecated in GCC and, with agreement with the GCC team, has been removed from the ABI https://github.com/ARM-software/abi-aa/issues/369 as it was not being maintained. ILP32 is not something that Arm's development teams want to support, so my apologies I can't review this.

 

https://github.com/llvm/llvm-project/pull/225939