[llvm] [AMDGPU][MC] Remove incorrect `_e32` suffix from `v_dot2c_f32_f16` and `v_dot4c_i32_i8` (PR #77993)

[Joe Nash via llvm-commits]

Sisyph wrote:

Do you want to strip _e32 on all subtargets? If so, you can set IsSingle = 1 in the VOPProfile for these instructions instead. If it varies per target then this looks ok.

https://github.com/llvm/llvm-project/pull/77993