printk: Tie printk_once / printk_deferred_once into .data.once for reset

printk: Tie printk_once / printk_deferred_once into .data.once for reset

In commit b1fca27d384e ("kernel debug: support resetting WARN*_ONCE")
we got the opportunity to reset state on the one shot messages,
without having to reboot.

However printk_once (printk_deferred_once) live in a different file
and didn't get the same kind of update/conversion, so they remain
unconditionally one shot, until the system is rebooted.

For example, we currently have:

  sched/rt.c: printk_deferred_once("sched: RT throttling activated\n");

..which could reasonably be tripped as someone is testing and tuning
a new system/workload and their task placements.  For consistency, and
to avoid reboots in the same vein as the original commit, we make these
two instances of _once the same as the WARN*_ONCE instances are.

Link: http://lkml.kernel.org/r/[email protected]
Cc: Andi Kleen <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Paul Gortmaker <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Petr Mladek <[email protected]>