gpio: mlxbf3: only get IRQ for device instance 0

gpio: mlxbf3: only get IRQ for device instance 0

The gpio-mlxbf3 driver interfaces with two GPIO controllers,
device instance 0 and 1. There is a single IRQ resource shared
between the two controllers, and it is found in the ACPI table for
device instance 0.  The driver should not attempt to get an IRQ
resource when probing device instance 1, otherwise the following
error is logged:
  mlxbf3_gpio MLNXBF33:01: error -ENXIO: IRQ index 0 not found

Signed-off-by: David Thompson <davthompson@nvidia.com>
Reviewed-by: Shravan Kumar Ramani <shravankr@nvidia.com>
Fixes: cd33f216d241 ("gpio: mlxbf3: Add gpio driver support")
Link: https://lore.kernel.org/r/20250613163443.1065217-1-davthompson@nvidia.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>