dm: firmware: Automatically bind child devices

To support scenarios where a firmware device node has subnodes that
have their own drivers automatically scan the DT and bind those when
the firmware device gets bound.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

drivers/firmware/firmware-uclass.c

@@ -7,4 +7,7 @@
 UCLASS_DRIVER(firmware) = {
 	.id		= UCLASS_FIRMWARE,
 	.name		= "firmware",
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+	.post_bind	= dm_scan_fdt_dev,
+#endif
 };