idevicebackup2: Use macro instead of plain AFC service name
idevicebackup2: Use macro instead of plain AFC service name

kalev/libimobiledevice,Tatsh/libimobiledevice,patweb/libimobiledevice,libimobiledevice-win32/libimobiledevice,upbit/libimobiledevice,libimobiledevice-win32/libimobiledevice,Tatsh/libimobiledevice,libimobiledevice/libimobiledevice,libimobiledevice/libimobiledevice,libimobiledevice-win32/libimobiledevice,patweb/libimobiledevice,kalev/libimobiledevice,libimobiledevice-win32/libimobiledevice,patweb/libimobiledevice,Tatsh/libimobiledevice,upbit/libimobiledevice,kalev/libimobiledevice,Tatsh/libimobiledevice,upbit/libimobiledevice