Task #11406: Beamformer can have a reduced staton set, so use correct one.

RTCP/Cobalt/GPUProc/src/cuda/SubbandProcs/BeamFormerPreprocessingStep.cc

@@ -50,8 +50,9 @@ namespace LOFAR
           "FFT-shift (beamformer)")),
 
         zeroing(ZeroingKernel::Parameters(ps,
-          ps.settings.antennaFields.size(),
-          ps.settings.beamFormer.nrDelayCompensationChannels)),
+          ps.settings.beamFormer.antennaFieldNames.size(),
+          ps.settings.beamFormer.nrDelayCompensationChannels,
+          "Zeroing (beamformer)")),
 
         delayCompensation(DelayAndBandPassKernel::Parameters(ps, false)),