i2c: Drop legacy callback .probe_new()

Now that all drivers are converted to the (new) .probe() callback, the
temporary .probe_new() can go away. \o/

Link: https://lore.kernel.org/linux-i2c/20230626094548.559542-1-u.kleine-koenig@pengutronix.de
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>