[llvm] AMDGPU/GlobalISel: Fix G_INTRINSIC_FPTRUNC_ROUND round mode operand type (PR #202734)

[Petar Avramovic via llvm-commits]

https://github.com/petar-avramovic commented:

Don't really understand what happens here but it works.
Now what would make much more sense to me would be to use 
(i32 RtzRoundMode) instead of (i32 0) for "non-updated patterns", there is one pattern with RtzRoundMode which is TImmLeaf

https://github.com/llvm/llvm-project/pull/202734