media: zr364xx: fix memory leak in zr364xx_start_readpipe

media: zr364xx: fix memory leak in zr364xx_start_readpipe

syzbot reported memory leak in zr364xx driver.
The problem was in non-freed urb in case of
usb_submit_urb() fail.

backtrace:
  [<ffffffff82baedf6>] kmalloc include/linux/slab.h:561 [inline]
  [<ffffffff82baedf6>] usb_alloc_urb+0x66/0xe0 drivers/usb/core/urb.c:74
  [<ffffffff82f7cce8>] zr364xx_start_readpipe+0x78/0x130 drivers/media/usb/zr364xx/zr364xx.c:1022
  [<ffffffff84251dfc>] zr364xx_board_init drivers/media/usb/zr364xx/zr364xx.c:1383 [inline]
  [<ffffffff84251dfc>] zr364xx_probe+0x6a3/0x851 drivers/media/usb/zr364xx/zr364xx.c:1516
  [<ffffffff82bb6507>] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396
  [<ffffffff826018a9>] really_probe+0x159/0x500 drivers/base/dd.c:576

Fixes: ccbf035ae5de ("V4L/DVB (12278): zr364xx: implement V4L2_CAP_STREAMING")
Cc: stable@vger.kernel.org
Reported-by: syzbot+af4fa391ef18efdd5f69@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>