[clang] [llvm] [RISCV][P-ext] Support Packed Load (PR #223313)

[Christian Herber via cfe-commits]

christian-herber-nxp wrote:

@topperc Seeing this makes me wonder why on RV32, load/store intrinsics for register pairs are not supported? Either through Zilsd or two load/stores.

https://github.com/llvm/llvm-project/pull/223313