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/cpu/imx8_cpu.c b/drivers/cpu/imx8_cpu.c
index abddbef..b8eb2d2 100644
--- a/drivers/cpu/imx8_cpu.c
+++ b/drivers/cpu/imx8_cpu.c
@@ -144,7 +144,7 @@
 	ofnode_for_each_subnode(node, dev_ofnode(dev->parent)) {
 		const char *device_type;
 
-		if (!ofnode_is_available(node))
+		if (!ofnode_is_enabled(node))
 			continue;
 
 		device_type = ofnode_read_string(node, "device_type");