dm: blk: add a device-probe hook for scanning disk partitions

Now that all the block device drivers have enable a probe hook, we will
call part_create_block_devices() to enumerate all the partitions and
create associated udevices when a block device is detected.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/block/blk-uclass.c

@@ -741,6 +741,10 @@ static int blk_post_probe(struct udevice *dev)
 		struct blk_desc *desc = dev_get_uclass_plat(dev);
 
 		part_init(desc);
+
+		if (desc->part_type != PART_TYPE_UNKNOWN &&
+		    part_create_block_devices(dev))
+			debug("*** creating partitions failed\n");
 	}
 
 	return 0;