staging: comedi: icp_multi: remove board reset during (*detach)

The icp_multi_reset() function currnelt does the following during the
(*auto_attach) and (*detach) of this driver:

  1) disables all interrupts and clears any pending requests
  2) resets the analog output channels to 0V (0..5V range)
  3) sets all digital output channels to 0

Interrupts are not used by this driver so the disable/clear when
detaching is not necessary.

Depending on the use, reseting the analog and digital outputs when the
driver is detached might not be desireable.

Remove the board reset during the (*detach) and use comedi_pci_detach()
directly.

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>