aco: Emit zero for the derivatives of uniforms.

Observed in a shader from Resident Evil Village.
This also helps prevent emitting invalid IR.

Cc: mesa-stable
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12599>
1 file changed