i2c: Update drivers to use enum for speed

Convert the obvious uses of i2c bus speeds to use the enum.

Use livetree access for code changes.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/i2c/rcar_iic.c b/drivers/i2c/rcar_iic.c
index 9d45f54..2a82eb0 100644
--- a/drivers/i2c/rcar_iic.c
+++ b/drivers/i2c/rcar_iic.c
@@ -248,7 +248,7 @@
 
 	rcar_iic_finish(dev);
 
-	return rcar_iic_set_speed(dev, 100000);
+	return rcar_iic_set_speed(dev, I2C_SPEED_STANDARD_RATE);
 }
 
 static const struct dm_i2c_ops rcar_iic_ops = {