i2c: i801: Fix the i2c-mux gpiod_lookup_table not being properly terminated

gpiod_add_lookup_table() expects the gpiod_lookup_table->table passed to
it to be terminated with a zero-ed out entry.

So we need to allocate one more entry then we will use.

Fixes: d308dfbf ("i2c: mux/i801: Switch to use descriptor passing")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>