power: supply: smb347-charger: IRQSTAT_D is volatile

[ Upstream commit c32ea07a30630ace950e07ffe7a18bdcc25898e1 ]

Fix failure when USB cable is connected:
smb347 2-006a: reading IRQSTAT_D failed

Fixes: 1502cfe1 ("smb347-charger: Fix battery status reporting logic for charger faults")

Tested-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>