staging: comedi: adv_pci1710: rename boardinfo 'have_irq'

For aesthetics, rename this member of the boardinfo to 'has_irq' and change
it to a bit-field flag.

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>