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/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c
index 3aa8ad1..2d3feca 100644
--- a/drivers/i2c/ast_i2c.c
+++ b/drivers/i2c/ast_i2c.c
@@ -110,7 +110,7 @@
 {
 	struct ast2500_scu *scu;
 
-	debug("Enabling I2C%u\n", dev->seq);
+	debug("Enabling I2C%u\n", dev_seq(dev));
 
 	/*
 	 * Get all I2C devices out of Reset.
@@ -307,7 +307,7 @@
 	struct ast_i2c_regs *regs = priv->regs;
 	ulong i2c_rate, divider;
 
-	debug("Setting speed for I2C%d to <%u>\n", dev->seq, speed);
+	debug("Setting speed for I2C%d to <%u>\n", dev_seq(dev), speed);
 	if (!speed) {
 		debug("No valid speed specified\n");
 		return -EINVAL;