gpio: nuvoton: Fix sgpio irq handle error

gpio: nuvoton: Fix sgpio irq handle error

The generic_handle_domain_irq() function calls irq_resolve_mapping().
Thus delete a duplicative irq_find_mapping() call
so that a stack trace and an RCU stall will be avoided.

Fixes: c4f8457d17ce ("gpio: nuvoton: Add Nuvoton NPCM sgpio driver")
Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20240506064244.1645922-1-JJLIU0@nuvoton.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>