i2c/designware: Constify struct device * parameter to dw_i2c_soc_dev_to_bus

dw_i2c_soc_dev_to_bus() does not need to modify the device
structure. Thus, this change makes the struct device * parameter to
dw_i2c_soc_dev_to_bus as const.

Change-Id: Ibf5c8d8127dff2ab2ccbd1f6b4f553e98e81955f
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40704
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/i2c/designware/dw_i2c.h

@@ -129,7 +129,7 @@ int dw_i2c_transfer(unsigned int bus,
  * -1 = failure
  * >=0 = logical bus number
  */
-int dw_i2c_soc_dev_to_bus(struct device *dev);
+int dw_i2c_soc_dev_to_bus(const struct device *dev);
 
 /*
  * Common device_operations implementation to initialize the i2c host