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/arch/x86/cpu/ivybridge/model_206ax.c b/arch/x86/cpu/ivybridge/model_206ax.c
index 55f7cc2..598ebcd 100644
--- a/arch/x86/cpu/ivybridge/model_206ax.c
+++ b/arch/x86/cpu/ivybridge/model_206ax.c
@@ -425,7 +425,7 @@
 
 static int cpu_x86_model_206ax_probe(struct udevice *dev)
 {
-	if (dev->seq == 0)
+	if (dev_seq(dev) == 0)
 		model_206ax_init(dev);
 
 	return 0;