power: supply: smb347-charger: Make smb347_set_writable() IRQ-safe

The smb347_set_writable() is used by interrupt handler and outside of it.
The interrupt should be disabled when the function is used outside of
interrupt handler in order to prevent racing with the interrupt context.
Add new parameter to smb347_set_writable() that allows to disable IRQ.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>