staging: comedi: daqboard2000: remove #if 0'ed out code in ao (*insn_write)

This code has been disabled since it's initial commit. It must not be
needed so just remove it.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>