powerpc/xics: Add missing of_node_put() in error path

The device node obtained with of_find_compatible_node() should be
released by calling of_node_put().  But it was not released when
of_get_property() failed.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
[mpe: Invert the sense of the if so we only need one return path]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/sysdev/xics/xics-common.c

@@ -446,10 +446,11 @@ static void __init xics_get_server_size(void)
 	np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xics");
 	if (!np)
 		return;
+
 	isize = of_get_property(np, "ibm,interrupt-server#-size", NULL);
-	if (!isize)
-		return;
+	if (isize)
 		xics_interrupt_server_size = be32_to_cpu(*isize);
+
 	of_node_put(np);
 }