leds: netxbig: Fix GPIO descriptor leak in error paths

leds: netxbig: Fix GPIO descriptor leak in error paths

The function netxbig_gpio_ext_get() acquires GPIO descriptors but
fails to release them when errors occur mid-way through initialization.
The cleanup callback registered by devm_add_action_or_reset() only
runs on success, leaving acquired GPIOs leaked on error paths.

Add goto-based error handling to release all acquired GPIOs before
returning errors.

Fixes: 9af512e81964 ("leds: netxbig: Convert to use GPIO descriptors")
Suggested-by: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20251031021620.781-1-vulab@iscas.ac.cn
Signed-off-by: Lee Jones <lee@kernel.org>