ACPI: Fixes device power states array overflow

Commit 28c2103d added new state ACPI_STATE_D3_COLD, so the device power
states array must be expanded by one also.

v2: Use ACPI_D_STATE_COUNT instead of number 5 for the array size.
Reported-by: Dan Carpenter <error27@gmail.com>
Suggested-by: Oldřich Jedlička <oldium.pro@seznam.cz>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

include/acpi/acpi_bus.h

@@ -210,7 +210,7 @@ struct acpi_device_power_state {
 struct acpi_device_power {
 	int state;		/* Current state */
 	struct acpi_device_power_flags flags;
-	struct acpi_device_power_state states[4];	/* Power states (D0-D3) */
+	struct acpi_device_power_state states[ACPI_D_STATE_COUNT];	/* Power states (D0-D3Cold) */
 };
 
 /* Performance Management */