staging: comedi: dyna_pci10xx: Don't bother configuring len_chanlist

In the Comedi "attach" and "auto_attach" handlers that set up the Comedi
subdevices, there is no need to initialize the `len_chanlist` member of
Comedi subdevices that do not support Comedi asynchronous streaming
commands.  They can be left set to the initial zeroed out value and
the Comedi core will change the `len_chanlist` member to 1 afterwards in
that case.  The "dyna_pci10xx" driver currently sets the `len_chanlist`
members to the same value as the `n_chan` ("number of channels") member,
but this is unnecessary as none of them support asynchronous streaming.
Remove the initialization of `len_chanlist` from all the subdevices.
This will affect the information reported by the COMEDI_SUBDINFO ioctl
slightly.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>