multimedia/pipewire: unbreak on FreeBSD < 13.2 after ea9c61f86374

In file included from ../src/modules/module-netjack2-manager.c:38:
../src/modules/module-netjack2/peer.c:2:10: fatal error: 'byteswap.h' file not found
#include <byteswap.h>

^~~~~~~~~~~~

PR: 273258