hung_task: Change sysctl_hung_task_check_count to 'int'

hung_task: Change sysctl_hung_task_check_count to 'int'

As 'sysctl_hung_task_check_count' is 'unsigned long' when this
value is assigned to max_count in check_hung_uninterruptible_tasks(),
it's truncated to 'int' type.

This causes a minor artifact: if we write 2^32 to sysctl.hung_task_check_count,
hung task detection will be effectively disabled.

With this fix, it will still truncate the user input to 32 bits, but
reading sysctl.hung_task_check_count reflects the actual truncated value.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/523FFF4E.9050401@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>