power: max8903_charger: set IRQF_ONESHOT if no primary handler is specified

If no primary handler is specified for threaded_irq then a
default one is assigned which always returns IRQ_WAKE_THREAD.
This handler requires the IRQF_ONESHOT, because the source of
interrupt is not disabled.

Signed-off-by: Saurabh Sengar <saurabh.truth@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>