[llvm] [AArch64] Restore always-inline behaviour for incompatible SME attributes. (PR #218727)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

> For those of us not familiar with SME, can you please provide some context on what the current check exists to protect against?

Across the various modes (indicated by the SME attributes), some operations are only legal in specific modes (or have behaviour changes between modes). The current check was added as a very conservative check for the default inliner (as noted on the linked issue, some of these checks could be relaxed). 

https://github.com/llvm/llvm-project/pull/218727