dm: Avoid accessing seq directly

At present various drivers etc. access the device's 'seq' member directly.
This makes it harder to change the meaning of that member. Change access
to go through a function instead.

The drivers/i2c/lpc32xx_i2c.c file is left unchanged for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/watchdog/ast_wdt.c b/drivers/watchdog/ast_wdt.c
index 0b8668d..f7b5a1a 100644
--- a/drivers/watchdog/ast_wdt.c
+++ b/drivers/watchdog/ast_wdt.c
@@ -113,7 +113,7 @@
 
 static int ast_wdt_probe(struct udevice *dev)
 {
-	debug("%s() wdt%u\n", __func__, dev->seq);
+	debug("%s() wdt%u\n", __func__, dev_seq(dev));
 	ast_wdt_stop(dev);
 
 	return 0;