tracing: Move trace_printk.h out of kernel.h

There's been complaints about trace_printk() being defined in kernel.h as it can increase the compilation time. As it is only used by some developers for debugging purposes, it should not be in kernel.h causing lots of wasted CPU cycles for those that do not ever care about it.

Instead, add a CONFIG_TRACE_PRINTK_DEBUGGING option that developers that do use it can set and not have to always remember to add #include <linux/trace_printk.h> to the files they add trace_printk() while debugging. It also means that those that do not have that config set will not have to worry about wasted CPU cycles as it is only include in the CFLAGS when the option is set, and its completely ignored otherwise.

Steven Rostedt (2):
tracing: Move non-trace_printk prototypes back to kernel.h
tracing: Add CONFIG_TRACE_PRINTK_DEBUGGING to clean up kernel.h

----

 .../driver_development_debugging_guide.rst         |  2 +-
 Makefile                                           |  5 +++++
 arch/powerpc/kvm/book3s_xics.c                     |  1 +
 drivers/gpu/drm/i915/gt/intel_gtt.h                |  1 +
 drivers/gpu/drm/i915/i915_gem.h                    |  1 +
 drivers/hwtracing/stm/dummy_stm.c                  |  4 ++++
 drivers/infiniband/hw/hfi1/trace_dbg.h             |  1 +
 drivers/usb/early/xhci-dbc.c                       |  1 +
 fs/ext4/inline.c                                   |  1 +
 include/linux/kernel.h                             | 19 ++++++++++++++++++-
 include/linux/sunrpc/debug.h                       |  1 +
 include/linux/trace_printk.h                       | 22 +++-------------------
 kernel/trace/Kconfig                               | 10 ++++++++++
 kernel/trace/ring_buffer_benchmark.c               |  1 +
 kernel/trace/trace.h                               |  1 +
 samples/fprobe/fprobe_example.c                    |  1 +
 samples/ftrace/ftrace-direct-modify.c              |  1 +
 samples/ftrace/ftrace-direct-multi-modify.c        |  1 +
 samples/ftrace/ftrace-direct-multi.c               |  2 +-
 samples/ftrace/ftrace-direct-too.c                 |  2 +-
 samples/ftrace/ftrace-direct.c                     |  2 +-
 21 files changed, 56 insertions(+), 24 deletions(-)