[LAU] rtirq: low priority limit

Hi Rui (and all), I'm attaching two small patches that adds a lower priority limit to the rtirq script (with a matching configuration variable). This is useful to have if you have a limited range of available priority "steps" because, for example, a distribution restricts the maximum priority a user is allowed to have. With this change you can make sure that the priority of all irq processes is higher than the priority of (say) the jackd process, no matter how many processes you have. Reasonable defaults are chosen if the variable is not configured. Do you think you could add this to your package? Thanks, -- Fernando PS: how about incorporating my previous "additions" as well in rtirq? (ie: irq priority change through udev when a soundcard is inserted and remembering priorities between sleep and resume).