sdr/pi4cxpsk: Use 'float' version of carg
sdr/pi4cxpsk: Use 'float' version of carg

Data are float anyway ...

Signed-off-by: Sylvain Munaut <349f318521b45672c77207abf1a5ed60eb011db1@246tNt.com>

marcelmaatkamp/gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr,marcelmaatkamp/gnuradio-osmocom-gmr,marcelmaatkamp/gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr