tracing: move tracing declarations from kernel.h to a dedicated header

tracing: move tracing declarations from kernel.h to a dedicated header

Tracing is a half of the kernel.h in terms of LOCs, although it's a
self-consistent part.  It is intended for quick debugging purposes and
isn't used by the normal tracing utilities.

Move it to a separate header.  If someone needs to just throw a
trace_printk() in their driver, they will not have to pull all the heavy
tracing machinery.

This is a pure move.

Link: https://lkml.kernel.org/r/20260116042510.241009-7-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>