cpumask: replace node_to_cpumask with cpumask_of_node.

Impact: cleanup

node_to_cpumask (and the blecherous node_to_cpumask_ptr which
contained a declaration) are replaced now everyone implements
cpumask_of_node.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/base/node.c b/drivers/base/node.c
index f8f578a..40b8097 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -24,7 +24,7 @@
 static ssize_t node_read_cpumap(struct sys_device *dev, int type, char *buf)
 {
 	struct node *node_dev = to_node(dev);
-	node_to_cpumask_ptr(mask, node_dev->sysdev.id);
+	const struct cpumask *mask = cpumask_of_node(node_dev->sysdev.id);
 	int len;
 
 	/* 2008/04/07: buf currently PAGE_SIZE, need 9 chars per 32 bits. */