i2c: at91_i2c: Change error return -ENODEV to -EINVAL

Change the error return value -ENODEV from to -EINVAL for more
reasonable.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

drivers/i2c/at91_i2c.c

@@ -190,7 +190,7 @@ static int at91_i2c_enable_clk(struct udevice *dev)
 
 	clk_rate = clk_get_rate(&clk);
 	if (!clk_rate)
-		return -ENODEV;
+		return -EINVAL;
 
 	bus->bus_clk_rate = clk_rate;