FP8: limit fader range

In case of VCA masters or otherwise the value can exceed the max
+6dB and internal_to_interface() returns a value > 1.0 which cannot
be represented on the physical fader (MIDI &0x7f wraps)

libs/surfaces/faderport8/fp8_strip.cc

@@ -360,6 +360,7 @@ FP8Strip::notify_fader_changed ()
 	float val = 0;
 	if (ac) {
 		val = ac->internal_to_interface (ac->get_value()) * 16368.f; /* 16 * 1023 */
+		val = std::max (0.f, std::min (1.f, val));
 	}
 	unsigned short mv = lrintf (val);
 	if (mv == _last_fader) {