gpio: pca953x: fix irq_domain_add_simple usage

We actually have to pass chip as the host_data parameter of
irq_domain_add_simple() as later on, it is used to initialize chip_data
in pca953x_gpio_irq_map(). Failing to do so is leading to a NULL pointer
dereference after calling irq_data_get_irq_chip_data() in
pca953x_irq_mask(), pca953x_irq_unmask(), pca953x_irq_bus_lock(),
pca953x_irq_bus_sync_unlock() and pca953x_irq_set_type().

Fixes regression introduced by commit
0e8f2fda (gpio: pca953x: use simple
irqdomain)

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>