dm: core: Drop ofnode_is_available()

This function is also available as ofnode_is_enabled(), so use that
instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/net/sja1105.c b/drivers/net/sja1105.c
index 4ca8709..48f044c 100644
--- a/drivers/net/sja1105.c
+++ b/drivers/net/sja1105.c
@@ -3316,7 +3316,7 @@
 	int rc;
 
 	if (ofnode_valid(dev_ofnode(dev)) &&
-	    !ofnode_is_available(dev_ofnode(dev))) {
+	    !ofnode_is_enabled(dev_ofnode(dev))) {
 		dev_dbg(dev, "switch disabled\n");
 		return -ENODEV;
 	}