Revert "activate_mapping: fflush the buffered data to smp_affinity"

This reverts commit 8bbc0ae.

Was causing a segfault:
#267

activate.c

@@ -76,7 +76,7 @@ static void activate_mapping(struct irq_info *info, void *data __attribute__((un
 
 	cpumask_scnprintf(buf, PATH_MAX, applied_mask);
 	ret = fprintf(file, "%s", buf);
-	if (ret < 0 || fflush(file)) {
+	if (ret < 0) {
 		log(TO_ALL, LOG_WARNING, "cannot change irq %i's affinity, add it to banned list", info->irq);
 		add_banned_irq(info->irq);
 		remove_one_irq_from_db(info->irq);