[llvm] [GlobalISel] Fix vector.deinterleave2 with <1 x float> results (PR #214718)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

Thanks - LGTM

There are also scalar interleaves but they currently fall back to SDAG.

https://github.com/llvm/llvm-project/pull/214718