[llvm] [AArch64] Use FMOVDr for clearing upper bits (PR #83107)

[Sam Tebbs via llvm-commits]

https://github.com/SamTebbs33 approved this pull request.

Looks good to me. I do have to ask if there's a chance the CPU will see `fmov dX, dX` as a NOP and therefore not zero the high bits.

https://github.com/llvm/llvm-project/pull/83107