staging: comedi: pcl724: remove interrupt support

Interrupt support in this driver is not complete.

Remove the #ifdef'ed out code in pcl724_attach() that validates
the interrupt number and does the request_irq().

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>