[llvm] [LV] Teach LoopVectorizationLegality about struct vector calls (PR #119221)

[David Sherwood via llvm-commits]

https://github.com/david-arm approved this pull request.

LGTM! Thanks for making all the changes. Perhaps wait a day in case @fhahn has any comments?

https://github.com/llvm/llvm-project/pull/119221