watch_queue: Free the alloc bitmap when the watch_queue is torn down

stable inclusion
from stable-v5.10.106
commit 06ab8444392acdbffb57869d6220fb6654a8c95e
bugzilla: https://gitee.com/openeuler/kernel/issues/I573US

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06ab8444392acdbffb57869d6220fb6654a8c95e



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

commit 7ea1a012 upstream.

Free the watch_queue note allocation bitmap when the watch_queue is
destroyed.

Fixes: c73be61c ("pipe: Add general notification queue support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>