gpiolib: fix lookup table matching

gpiolib: fix lookup table matching

If on any iteration in gpiod_find(), gpio_desc_table_match() returns
NULL (which is normal and expected), we never reinitialize desc back to
ERR_PTR(-ENOENT) and if we don't find a match later on, we will return
NULL causing a NULL-pointer dereference in users not expecting it. Don't
initialize desc, but return ERR_PTR(-ENOENT) explicitly at the end of
the function.

Fixes: 9700b0fccf38 ("gpiolib: allow multiple lookup tables per consumer")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/00107523-7737-4b92-a785-14ce4e93b8cb@samsung.com/
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260108102314.18816-1-bartosz.golaszewski@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>