network-unix: create_cancel_fd() can be static
network-unix: create_cancel_fd() can be static

This function is only used in network-unix.c, and therefore can be made
static.

Signed-off-by: Paul Cercueil <a027184a55211cd23e3f3094f1fdc728df5e0500@crapouillou.net>

analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio