i2c-dev: Delete empty detach_client callback

Implementing detach_client is optional, so there is no point in
an empty implementation.

Likewise, i2c driver IDs are optional, and we don't need one.

Signed-off-by: Jean Delvare <[e-mail]>

drivers/i2c/i2c-dev.c

···
 	return 0;
 }
 
-static int i2cdev_detach_client(struct i2c_client *client)
-{
-	return 0;
-}
-
 static struct i2c_driver i2cdev_driver = {
 	.driver = {
 		.name	= "dev_driver",
 	},
-	.id		= I2C_DRIVERID_I2CDEV,
 	.attach_adapter	= i2cdev_attach_adapter,
 	.detach_adapter	= i2cdev_detach_adapter,
-	.detach_client	= i2cdev_detach_client,
 };
 
 /* ------------------------------------------------------------------------- */

include/linux/i2c-id.h

···
 #define I2C_DRIVERID_M52790 	95      /* Mitsubishi M52790SP/FP AV switch */
 #define I2C_DRIVERID_CS5345	96	/* cs5345 audio processor	*/
 
-#define I2C_DRIVERID_I2CDEV	900
-
 #define I2C_DRIVERID_OV7670 1048	/* Omnivision 7670 camera */
 
 /*