[CPUFREQ] speedstep_detect_speed might not reenable interrupts

From Samuel Thibault

local_irq_save() is called at the beginning of speedstep_detect_speeds,
but local_irq_restore() is not called on I/O errors.

arch/i386/kernel/cpu/cpufreq/speedstep-ich.c

@@ -538,8 +538,10 @@ static int speedstep_detect_speeds (void)
 	for (i=0; i<2; i++) {
 		/* read the current state */
 		result = speedstep_get_state(&state);
-		if (result)
+		if (result) {
+			local_irq_restore(flags);
 			return result;
+		}
 
 		/* save the correct value, and switch to other */
 		if (state == SPEEDSTEP_LOW) {