gpio: altera: Add missed base and label initialisations

gpio: altera: Add missed base and label initialisations

During conversion driver to modern APIs the base field initial value
of the GPIO chip was moved from -1 to 0, which triggers a warning.
Add missed base initialisation as it was in the original code.

Initialise the GPIO chip label correctly as it was done by
of_mm_gpiochip_add_data() before the below mentioned change.

Fixes: 50dded8d9d62 ("gpio: altera: Drop legacy-of-mm-gpiochip.h header")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241118095402.516989-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>