ARM: EXYNOS: Remove unneeded __ref annotation for cpu_die function

The __ref annotation for exynos_cpu_die() is not needed because the
function does not reference any __init/__exit symbol or call.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/platsmp.c

@@ -373,7 +373,7 @@ static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
  *
  * Called with IRQs disabled
  */
-static void __ref exynos_cpu_die(unsigned int cpu)
+static void exynos_cpu_die(unsigned int cpu)
 {
 	int spurious = 0;