i2c: i801: Save register SMBSLVCMD value only once

Saving the original value of register SMBSLVCMD in
i801_enable_host_notify() doesn't work, because this function is
called not only at probe time but also at resume time. Do it in
i801_probe() instead, so that the saved value is not overwritten at
resume time.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: 22e94bd6 ("i2c: i801: store and restore the SLVCMD register at load and unload")
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org	# v4.10+