[llvm] [AMDGPU][MC] Disallow op_sel in v_dot4 and v_dot8 with 4- or 8-bit packed data (PR #100485)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

I am reading SP3 pseudocode, looks like OPSEL is not used on any of the targets with this. These instructions also do not have OPSEL flag in SP3. So I guess we need to set it to zero on all targets.

https://github.com/llvm/llvm-project/pull/100485