ACPI / PM: Fix error code path for power resources initialization

Commit 781d737c

 (ACPI: Drop power resources driver) introduced a
bug in the power resources initialization error code path causing
a NULL pointer to be referenced in acpi_release_power_resource()
if there's an error triggering a jump to the 'err' label in
acpi_add_power_resource().  This happens because the list_node
field of struct acpi_power_resource has not been initialized yet
at this point and doing a list_del() on it is a bad idea.

To prevent this problem from occuring, initialize the list_node
field of struct acpi_power_resource upfront.

Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.9+ <stable@vger.kernel.org>
Acked-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>