rtc: cpcap: fix improper use of IRQ_NONE for request_threaded_irq

There's a funny typo where IRQ_NONE is used instead of IRQF_TRIGGER_NONE
for request_threaded_irq(). Let's fix it before it gets copied elsewhere.

Fixes: dd3bf50b ("rtc: cpcap: new rtc driver")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>