drm/kms: Simplify setup of the initial I2C encoder config.

In most use cases the driver will be using the same static config all
the time: interpreting i2c_board_info::platform_data as the default
config we can can save the GPU driver a redundant set_config() call.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_encoder_slave.c

@@ -41,6 +41,9 @@
  * &drm_encoder_slave. The @slave_funcs field will be initialized with
  * the hooks provided by the slave driver.
  *
+ * If @info->platform_data is non-NULL it will be used as the initial
+ * slave config.
+ *
  * Returns 0 on success or a negative errno on failure, in particular,
  * -ENODEV is returned when no matching driver is found.
  */
@@ -85,6 +88,10 @@ int drm_i2c_encoder_init(struct drm_device *dev,
 	if (err)
 		goto fail_unregister;
 
+	if (info->platform_data)
+		encoder->slave_funcs->set_config(&encoder->base,
+						 info->platform_data);
+
 	return 0;
 
 fail_unregister: