[POWERPC] powermac: Constify & voidify get_property()

Now that get_property() returns a void *, there's no need to cast its
return value. Also, treat the return value as const, so we can
constify get_property later.

powermac platform & macintosh driver changes.

Built for pmac32_defconfig, g5_defconfig

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/macintosh/via-pmu-led.c b/drivers/macintosh/via-pmu-led.c
index 5189d54..179af10 100644
--- a/drivers/macintosh/via-pmu-led.c
+++ b/drivers/macintosh/via-pmu-led.c
@@ -120,7 +120,7 @@
 	dt = of_find_node_by_path("/");
 	if (dt == NULL)
 		return -ENODEV;
-	model = (const char *)get_property(dt, "model", NULL);
+	model = get_property(dt, "model", NULL);
 	if (model == NULL)
 		return -ENODEV;
 	if (strncmp(model, "PowerBook", strlen("PowerBook")) != 0 &&