[llvm] [Hexagon] Provide a custom decoder for Y4_crswap10 (PR #153849)

[Alexey Karyakin via llvm-commits]

quic-akaryaki wrote:

I think it can be easier to fix this by defining double-size crswap the same way as single crswap. The difference is in the single-register crswap, sgp0/1 are hard-coded in the instruction syntax, while the double-register one uses a register reference (`$sgp10`). Since there is only one register that can be used, there should be no reason to store it as an argument.

https://github.com/llvm/llvm-project/pull/153849