staging: comedi: me4000: fix me4000_detach()

There is no real reason to reset the board when detaching. The comedi core
will ensure that any commands are canceled before the detach.

But the PLX interrupts should be disabled.

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>