timers: Move timer sysctl into the timer code

This is part of the effort to reduce kernel/sysctl.c to only contain the
core logic.

Signed-off-by: tangmeng <tangmeng@uniontech.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220215065019.7520-1-tangmeng@uniontech.com