ptp: ptp_read should not release queue

Firstly, queue is not the memory allocated in ptp_read;
Secondly, other processes may block at ptp_read and wait for conditions to be
met to perform read operations.

Acked-by: Richard Cochran <richardcochran@gmail.com>
Reported-and-tested-by:  <syzbot+df3f3ef31f60781fa911@syzkaller.appspotmail.com>
Fixes: 8f5de6fb

 ("ptp: support multiple timestamp event readers")
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Link: https://lore.kernel.org/r/tencent_18747D76F1675A3C633772960237544AAA09@qq.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>