i2c: Fix i2c speed command

This corrects i2c core to interpret the value returned by
i2c_set_bus_speed as a success indicator rather than the
actual speed that was set. When i2c_set_bus_speed returns
a failure code, the speed is unknown so the adapter speed
is set to zero.

Signed-off-by: Darwin Rambo <drambo@broadcom.com>
Reviewed-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Steve Rae <srae@broadcom.com>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>

drivers/i2c/i2c_core.c

@@ -349,7 +349,7 @@ unsigned int i2c_set_bus_speed(unsigned int speed)
 		return 0;
 	ret = I2C_ADAP->set_bus_speed(I2C_ADAP, speed);
 	if (gd->flags & GD_FLG_RELOC)
-		I2C_ADAP->speed = ret;
+		I2C_ADAP->speed = (ret == 0) ? speed : 0;
 
 	return ret;
 }