ARM: EXYNOS: Use wfi macro in platform_do_lowpower

This patch is originally based on commit b3377d18 ("ARM: 7064/1:
vexpress: Use wfi macro in platform_do_lowpower.")

Current Exynos CPU hotplug code includes a hardcoded WFI instruction,
in ARM encoding. When the kernel is compiled in Thumb-2 mode, this
is invalid and causes the machine to hang hard when a CPU is offlined.

Use wfi macro instead of the hardcoded WFI instruction.
Signed-off-by: Leela Krishna Amudala <leela.krishna@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/hotplug.c

@@ -46,13 +46,7 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
 		if (cpu == 1)
 			exynos_cpu_power_down(cpu);
 
-		/*
-		 * here's the WFI
-		 */
-		asm(".word	0xe320f003\n"
-		    :
-		    :
-		    : "memory", "cc");
+		wfi();
 
 		if (pen_release == cpu_logical_map(cpu)) {
 			/*