cpuidle: power_usage should be declared signed integer

power_usage is always assigned a negative value and should be declared
a signed integer

Signed-off-by: Boris Ostrovsky <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/cpuidle/governors/menu.c

···
 {
 	struct menu_device *data = &__get_cpu_var(menu_devices);
 	int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
-	unsigned int power_usage = -1;
+	int power_usage = -1;
 	int i;
 	int multiplier;
 	struct timespec t;

include/linux/cpuidle.h

···
 
 	unsigned int	flags;
 	unsigned int	exit_latency; /* in US */
-	unsigned int	power_usage; /* in mW */
+	int		power_usage; /* in mW */
 	unsigned int	target_residency; /* in US */
 	unsigned int    disable;