staging: comedi: drivers: free_irq() in comedi_legacy_detach()

staging: comedi: drivers: free_irq() in comedi_legacy_detach()

All the legacy comedi drivers now call comedi_legacy_detach()
either directly or as part of their (*detach). Move the free_irq()
into comedi_legacy_detach() so that the drivers don't have to
deal with it.

For drivers that then only call comedi_legacy_detach() in their
private (*detach), remove the private function and use the helper
directly for the (*detach).

The amplc_pc236 and ni_labpc drivers are hybrid legacy/PCI drivers.
In the detach of a PCI board free_irq() still needs to be handled
by the driver.

The pcl724 and pcl726 drivers currently have the free_irq() #ifdef'ed
out. The comedi_legacy_detach() function sanity checks that the irq
has been requested before freeing it so they are safe to convert.

For aesthetic reasons, move the #ifdef unused chunk in the pcl816
driver up to the previous #ifdef unused block.

The pcmio and pcmuio drivers request multiple irqs and handle the
freeing of them. Remove the 'dev->irq = irq[0]' in those drivers
so that comedi_legacy_detach() does not attempt to free the 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>