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/i2c-cdns.c b/drivers/i2c/i2c-cdns.c
index ff3956d..ac15da2 100644
--- a/drivers/i2c/i2c-cdns.c
+++ b/drivers/i2c/i2c-cdns.c
@@ -213,7 +213,7 @@
 	unsigned long speed_p = speed;
 	int ret = 0;
 
-	if (speed > 400000) {
+	if (speed > I2C_SPEED_FAST_RATE) {
 		debug("%s, failed to set clock speed to %u\n", __func__,
 		      speed);
 		return -EINVAL;