ARM: imx: Add missing of_node_put()

After finishing using device node got from of_find_compatible_node(),
of_node_put() needs to be called.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/platsmp.c

@@ -109,6 +109,7 @@ static void __init ls1021a_smp_prepare_cpus(unsigned int max_cpus)
 
 	np = of_find_compatible_node(NULL, NULL, "fsl,ls1021a-dcfg");
 	dcfg_base = of_iomap(np, 0);
+	of_node_put(np);
 	BUG_ON(!dcfg_base);
 
 	paddr = __pa_symbol(secondary_startup);