led: Mark existing driver as legacy

The existing 'led' command does not support driver model. Rename it to
indicate that it is legacy code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ziping Chen <techping.chan@gmail.com>
diff --git a/cmd/Makefile b/cmd/Makefile
index ef1406b..19d450e 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -78,7 +78,7 @@
 obj-$(CONFIG_CMD_JFFS2) += jffs2.o
 obj-$(CONFIG_CMD_CRAMFS) += cramfs.o
 obj-$(CONFIG_CMD_LDRINFO) += ldrinfo.o
-obj-$(CONFIG_LED_STATUS_CMD) += led.o
+obj-$(CONFIG_LED_STATUS_CMD) += legacy_led.o
 obj-$(CONFIG_CMD_LICENSE) += license.o
 obj-y += load.o
 obj-$(CONFIG_LOGBUFFER) += log.o