Change the value of UIO_IRQ_NONE -2 to 0.  0 is well defined in the rest
of the kernel as the value to indicate an irq has not been assigned.

Update the calls to request_irq and free_irq to only ignore UIO_IRQ_NONE
and UIO_IRQ_CUSTOM allowing the rest of the kernel's possible irq
numbers to be used.
Signed-off-by: NEric W. Biederman <ebiederm@aristanetworks.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NHans J. Koch <hjk@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>