ALSA: hda/cirrus_scodec_test: Fix incorrect setup of gpiochip

ALSA: hda/cirrus_scodec_test: Fix incorrect setup of gpiochip

Set gpiochip parent to the struct device of the dummy GPIO driver
so that the software node will be associated with the GPIO chip.

The recent commit e5d527be7e698 ("gpio: swnode: don't use the
swnode's name as the key for GPIO lookup") broke cirrus_scodec_test,
because the software node no longer gets associated with the GPIO
driver by name.

Instead, setting struct gpio_chip.parent to the owning struct device
will find the node using a normal fwnode lookup.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 2144833e7b414 ("ALSA: hda: cirrus_scodec: Add KUnit test")
Link: https://patch.msgid.link/20260113130954.574670-1-rf@opensource.cirrus.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>