ARM: OMAP2: mach-omap2/pm.c build fix

This patch fix the following build problem:

  CC      arch/arm/mach-omap2/pm.o
arch/arm/mach-omap2/pm.c: In function 'omap2_pm_init':
arch/arm/mach-omap2/pm.c:840: warning: passing argument 2 of 'sysfs_create_file' from incompatible pointer type
Signed-off-by: Carlos Eduardo Aguiar <carlos.aguiar@indt.org.br>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/pm.c

@@ -837,7 +837,7 @@ int __init omap2_pm_init(void)
 	suspend_set_ops(&omap_pm_ops);
 	pm_idle = omap2_pm_idle;
 
-	error = sysfs_create_file(power_kobj, &sleep_while_idle_attr);
+	error = sysfs_create_file(power_kobj, &sleep_while_idle_attr.attr);
 	if (error)
 		printk(KERN_ERR "sysfs_create_file failed: %d\n", error);