watchdog: move watchdog sysctl interface to watchdog.c

Move watchdog syscl interface to watchdog.c.
Use register_sysctl() to register the sysctl interface to avoid
merge conflicts when different features modify sysctl.c at the same time.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2 files changed