hwmon: (hp-wmi-sensors) Check if WMI event data exists

The BIOS can choose to return no event data in response to a
WMI event, so the ACPI object passed to the WMI notify handler
can be NULL.

Check for such a situation and ignore the event in such a case.

Fixes: 23902f98 ("hwmon: add HP WMI Sensors driver")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Message-ID: <20240901031055.3030-2-W_Armin@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>