ARM: hisi: check of_iomap and fix missing of_node_put

of_find_compatible_node() returns a device node with refcount incremented
and thus needs an explicit of_node_put(). Further relying on an unchecked
of_iomap() which can return NULL is problematic here, after all ctrl_base
is critical enough for hix5hd2_set_cpu() to call BUG() if not available
so a check seems mandated here.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
0002 Fixes: commit 06cc5c1d4d ("ARM: hisi: enable hix5hd2 SoC")
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>

arch/arm/mach-hisi/hotplug.c

@@ -173,11 +173,15 @@ static bool hix5hd2_hotplug_init(void)
 	struct device_node *np;
 
 	np = of_find_compatible_node(NULL, NULL, "hisilicon,cpuctrl");
-	if (np) {
-		ctrl_base = of_iomap(np, 0);
-		return true;
-	}
+	if (!np)
 		return false;
+
+	ctrl_base = of_iomap(np, 0);
+	of_node_put(np);
+	if (!ctrl_base)
+		return false;
+
+	return true;
 }
 
 void hix5hd2_set_cpu(int cpu, bool enable)