ARM: OMAP: Fix warning in pm.c

ARM: OMAP2: Fix warning in pm.c:

arch/arm/mach-omap2/pm.c: In function 'omap2_pm_init':
arch/arm/mach-omap2/pm.c:854: warning: ignoring return value
of 'subsys_create_file', declared with attribute
warn_unused_result

Signed-off-by: Dirk Behme <dirk.behme_at_gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/pm.c

@@ -851,7 +851,9 @@ int __init omap2_pm_init(void)
 	pm_set_ops(&omap_pm_ops);
 	pm_idle = omap2_pm_idle;
 
-	subsys_create_file(&power_subsys, &sleep_while_idle_attr);
+	l = subsys_create_file(&power_subsys, &sleep_while_idle_attr);
+	if (l)
+		printk(KERN_ERR "subsys_create_file failed: %d\n", l);
 
 	return 0;
 }