Staging: comedi: reorder check in pcmmio_attach()

The check for dio_num_asics is used to determine if there is more than 1 irq.
If it is false then irq[1] is past the end of the array.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>