media: uvcvideo: Fix memory leak in uvc_gpio_parse

media: uvcvideo: Fix memory leak in uvc_gpio_parse

[ Upstream commit f0f078457f18f10696888f8d0e6aba9deb9cde92 ]

Previously the unit buffer was allocated before checking the IRQ for
privacy GPIO. In case of error, the unit buffer was leaked.

Allocate the unit buffer after the IRQ to avoid it.

Addresses-Coverity-ID: 1474639 ("Resource leak")

Fixes: 2886477ff987 ("media: uvcvideo: Implement UVC_EXT_GPIO_UNIT")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>