Network backend: Fix call of command READBUF
Network backend: Fix call of command READBUF

The prototype of the READBUF command has been modified in the
IIO Daemon, so it needs to be modified there too.

Signed-off-by: Paul Cercueil <73d292422978d45c9eeef455bb1b24a0db453722@analog.com>

gburca/libiio,sensarliar/libiio,analogdevicesinc/libiio,Sunderfield/libiio,gburca/libiio,gburca/libiio,Sunderfield/libiio,Sunderfield/libiio,analogdevicesinc/libiio,sensarliar/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,sensarliar/libiio