freedreno/ir3/cp: fix cmps folding

freedreno/ir3/cp: fix cmps folding

When we start doing cp iteratively, we hit the case that we've already
`cmps.s.*` into a `cmps.s.ne p0.x, ...`..  when we try to do that again
we can invert the logic condition.  So check specifically the condition
to prevent this.

TODO we could maybe be more clever about this to combine conditions.
But why isn't that happening in nir?  For example, see
dEQP-GLES31.functional.ssbo.layout.single_basic_array.packed.bool

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5048>