demo/ao_mmap: remove msync() call
demo/ao_mmap: remove msync() call

The msync() call doesn't seem to work on Comedi devices, and seems a bit
pointless anyway, as it is meant for use on files with a backing store.
Remove it.

olsonse/comedilib,olsonse/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,olsonse/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib,olsonse/comedilib,Linux-Comedi/comedilib,Linux-Comedi/comedilib