[llvm] [llvm][AArch64] Fix Arm 32 bit build warnings (PR #90862)

[David Spickett via llvm-commits]

DavidSpickett wrote:

I expect the immediate was never going to be large enough for this to be a problem, but it'll reduce some noise on the build bot.

https://github.com/llvm/llvm-project/pull/90862