Plugins: Clip NOVA functions should update unit-> variables

[jamshark70]

Bug reported on the mailing list: kr inputs to an ar Clip unit produce a sawtooth wave when changed.

This is because the original author of the SIMD calculation functions (38f2d28) forgot to update the struct member variables with new data from the inputs, meaning that every subsequent control cycle would attempt to ramp to the new value.

(
/* Start the synth, everything is correct... */
a = {
    arg control = 0.2;
    Clip.ar(DC.ar(), control, 0.4);
}.scope;
)

/* Until I change the control value */
a.set(\control, 0.25);

/* At this point I hear and see high-pitched oscillation that's
samplerate-dependant. */