ARM: EXYNOS: mcpm rename the power_down_finish

Since commit 166aaf39 ("ARM: 8029/1: mcpm: Rename the power_down_finish()
functions to be less confusing") changed the name of power_down_finish to
wait_for_cpu_powerdown, so use new member name wait_for_cpu_powerdown.
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/mcpm-exynos.c

@@ -235,7 +235,7 @@ static void exynos_power_down(void)
 	/* Not dead at this point?  Let our caller cope. */
 }
 
-static int exynos_power_down_finish(unsigned int cpu, unsigned int cluster)
+static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
 {
 	unsigned int tries = 100;
 	unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
@@ -261,7 +261,7 @@ static int exynos_power_down_finish(unsigned int cpu, unsigned int cluster)
 static const struct mcpm_platform_ops exynos_power_ops = {
 	.power_up		= exynos_power_up,
 	.power_down		= exynos_power_down,
-	.power_down_finish	= exynos_power_down_finish,
+	.wait_for_powerdown	= exynos_wait_for_powerdown,
 };
 
 static void __init exynos_mcpm_usage_count_init(void)