staging: comedi: addi_apci_1564: fix use of apci1564_reset() to disable DI interrupts

apci1564_cos_insn_config() is currently using apci1564_reset() to disable
digital input interrupts when the configuration operation is
COMEDI_DIGITAL_TRIG_DISABLE.  However, this is incorrect as the device reset
function also resets the registers for the digital outputs, timer, watchdog, and
counters as well.  Replace the reset function call with a direct disabling of
just the digital input interrupts.

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