[clang] [AArch64][SME] Remove immediate argument restriction for svldr and svstr (PR #68565)

[Sam Tebbs via cfe-commits]

SamTebbs33 wrote:

I've decided to keep this PR up for the patch that modifies the codegen and IR intrinsic since there's a lot of good relevant review of that here. I've made a [new PR](https://github.com/llvm/llvm-project/pull/68908) with the separated changes that just modify the clang builtin. This PR will later be rebased on top of that PR after it's merged.

https://github.com/llvm/llvm-project/pull/68565