ARM: EXYNOS: allow cpuidle driver usage on Exynos3250 SoC

Register cpuidle platform device on Exynos3250 SoC allowing EXYNOS
cpuidle driver usage on this SoC.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: NKyungmin Park <kyungmin.park@samsung.com>
Tested-by: NChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: NKukjin Kim <kgene@kernel.org>

arch/arm/mach-exynos/exynos.c

@@ -219,6 +219,7 @@ static void __init exynos_dt_machine_init(void)
 	    of_machine_is_compatible("samsung,exynos4212") ||
 	    (of_machine_is_compatible("samsung,exynos4412") &&
 	     of_machine_is_compatible("samsung,trats2")) ||
+	    of_machine_is_compatible("samsung,exynos3250") ||
 	    of_machine_is_compatible("samsung,exynos5250"))
 		platform_device_register(&exynos_cpuidle);