media: gspca/sq905.c: fix uninitialized variable

stable inclusion
from stable-5.10.36
commit 80ba39ec7cc9b8683dc9c0b6943d2861c3e9be56
bugzilla: 51867
CVE: NA

--------------------------------

[ Upstream commit eaaea468 ]

act_len can be uninitialized if usb_bulk_msg() returns an error.
Set it to 0 to avoid a KMSAN error.
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: syzbot+a4e309017a5f3a24c7b3@syzkaller.appspotmail.com
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/media/usb/gspca/sq905.c

@@ -158,7 +158,7 @@ static int
 sq905_read_data(struct gspca_dev *gspca_dev, u8 *data, int size, int need_lock)
 {
 	int ret;
-	int act_len;
+	int act_len = 0;
 
 	gspca_dev->usb_buf[0] = '\0';
 	if (need_lock)