gpio: fix uninit-value in swnode_find_gpio

gpio: fix uninit-value in swnode_find_gpio

Fix an issue detected by the Smatch tool:

drivers/gpio/gpiolib-swnode.c:78 swnode_find_gpio() error:
uninitialized symbol 'ret'.

The issue occurs because the 'ret' variable may be used without
initialization if the for_each_gpio_property_name loop does not run.
This could lead to returning an undefined value, causing unpredictable
behavior.

Initialize 'ret' to 0 before the loop to ensure the function
returns an error code if no properties are parsed, maintaining proper
error handling.

Fixes: 9e4c6c1ad ("Merge tag 'io_uring-6.12-20241011' of git://git.kernel.dk/linux")
Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>
Link: https://lore.kernel.org/r/20241026090642.28633-1-surajsonawane0215@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>