Input: palmas-pwrbutton - use IRQF_ONESHOT

make C=2 CHECK="scripts/coccicheck" MODE=report COCCI=scripts/coccinelle/misc/irqf_oneshot.cocci ./drivers/input/misc/palmas-pwrbutton.o
Reports:
drivers/input/misc/palmas-pwrbutton.c:213:9-29: ERROR: Threaded IRQ with no primary handler requested without IRQF_ONESHOT

Palmas power button just needs threaded IRQ handler since I2C operations
are involved and there is nothing in non-threaded primary handler we could
do.

So mark the request with ONESHOT as it should have been done in these
cases.

Fixes: adff5962 ("Input: introduce palmas-pwrbutton")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>