staging: comedi: adv_pci_dio: disable channel freeze outside of switch

For aesthetics, move the disable of the channel freeze for the PCI-1752
and PCI-1756 boards out of the switch used to disable and clear interrupts.

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>