[llvm] [RISCV][GISel] Remove source constraint from selectCopy and use it fo… (PR #67207)

[Craig Topper via llvm-commits]

topperc wrote:

> Test case?

I don't have a test case because it wasn't technically wrong. It was different than other targets and I don't know why.

https://github.com/llvm/llvm-project/pull/67207