comms/liquid-dsp: add dotprod_crcf_copy on powerpc64*

Fixes linking of reverse dependencies on powerpc64*:
: && /usr/bin/c++ -O2 -pipe -mcpu=power9 -fstack-protector-strong -fno-strict-aliasing -mcpu=power9 -O2 -pipe -mcpu=power9 -fstack-protector-strong -fno-strict-aliasing -mcpu=power9 -DNDEBUG -Wl,--undefined-version -Xlinker --dependency-file=src/CMakeFiles/inspectrum.dir/link.d src/CMakeFiles/inspectrum.dir/inspectrum_autogen/mocs_compilation.cpp.o src/CMakeFiles/inspectrum.dir/abstractsamplesource.cpp.o src/CMakeFiles/inspectrum.dir/amplitudedemod.cpp.o src/CMakeFiles/inspectrum.dir/cursor.cpp.o src/CMakeFiles/inspectrum.dir/cursors.cpp.o src/CMakeFiles/inspectrum.dir/main.cpp.o src/CMakeFiles/inspectrum.dir/fft.cpp.o src/CMakeFiles/inspectrum.dir/frequencydemod.cpp.o src/CMakeFiles/inspectrum.dir/mainwindow.cpp.o src/CMakeFiles/inspectrum.dir/inputsource.cpp.o src/CMakeFiles/inspectrum.dir/phasedemod.cpp.o src/CMakeFiles/inspectrum.dir/plot.cpp.o src/CMakeFiles/inspectrum.dir/plots.cpp.o src/CMakeFiles/inspectrum.dir/plotview.cpp.o src/CMakeFiles/inspectrum.dir/samplebuffer.cpp.o src/CMakeFiles/inspectrum.dir/samplesource.cpp.o src/CMakeFiles/inspectrum.dir/spectrogramcontrols.cpp.o src/CMakeFiles/inspectrum.dir/spectrogramplot.cpp.o src/CMakeFiles/inspectrum.dir/threshold.cpp.o src/CMakeFiles/inspectrum.dir/traceplot.cpp.o src/CMakeFiles/inspectrum.dir/tuner.cpp.o src/CMakeFiles/inspectrum.dir/tunertransform.cpp.o src/CMakeFiles/inspectrum.dir/util.cpp.o -o src/inspectrum -Wl,-rpath,/usr/local/lib/qt6:/usr/local/lib: /usr/local/lib/qt6/libQt6Widgets.so.6.11.1 /usr/local/lib/qt6/libQt6Concurrent.so.6.11.1 /usr/local/lib/libfftw3f.so /usr/local/lib/libliquid.so /usr/local/lib/qt6/libQt6Gui.so.6.11.1 /usr/local/lib/libGLX.so /usr/local/lib/libOpenGL.so /usr/local/lib/qt6/libQt6Core.so.6.11.1 -pthread -Wl,-rpath-link,/usr/local/lib/qt6 && :
ld: error: undefined reference: dotprod_rrrf_copy

referenced by /usr/local/lib/libliquid.so (disallowed by --no-allow-shlib-undefined)

ld: error: undefined reference: dotprod_crcf_copy

referenced by /usr/local/lib/libliquid.so (disallowed by --no-allow-shlib-undefined)

c++: error: linker command failed with exit code 1 (use -v to see invocation)