gpio: graniterapids: Add missing raw_spinlock_init()

Add the missing raw_spin_lock_init() call to gnr_gpio_probe().

Fixes: ecc4b141

 ("gpio: Add Intel Granite Rapids-D vGPIO driver")
Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240625135343.673745-1-aapo.vienamo@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>