ARM i.MX27 pm: return gracefully on different socs

Code called from an initcall can be maybe called for
machines it's not intended for. So check for valid
machines and return gracefully if an incompatible machine
is found.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-imx/pm-imx27.c b/arch/arm/mach-imx/pm-imx27.c
index afc17ce..6bf81ce 100644
--- a/arch/arm/mach-imx/pm-imx27.c
+++ b/arch/arm/mach-imx/pm-imx27.c
@@ -39,6 +39,9 @@
 
 static int __init mx27_pm_init(void)
 {
+	if (!cpu_is_mx27())
+		return 0;
+
 	suspend_set_ops(&mx27_suspend_ops);
 	return 0;
 }