Input: tc3589x-keypad - set IRQF_ONESHOT flag to ensure IRQ request

Since commit 1c6c6952 ("genirq: Reject
bogus threaded irq requests") threaded IRQs without a primary handler
need to be requested with IRQF_ONESHOT, otherwise the request will fail.

Currently, plat->irqtype is only set to IRQF_TRIGGER_FALLING.  This
patch sets the ONESHOT flag directly in request_threaded_irq() to
enforce the flag without being affected by future changes to
plat->irqtype.

Generated by: scripts/coccinelle/misc/irqf_oneshot.cocci

Signed-off-by: Valentin Rothberg <Valentin.Rothberg@lip6.fr>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>