drm/i915/gt: Start adding module oriented dmesg output

When trying to analyse bug reports from CI, customers, etc. it can be
difficult to work out exactly what is happening on which GT in a
multi-GT system. So add GT oriented debug/error message wrappers. If
used instead of the drm_ equivalents, you get the same output but with
a GT# prefix on it.

v2: Go back to using lower case names (combined review feedback).
Convert intel_gt.c as a first step.
v3: Add gt_err_ratelimited() as well, undo one conversation that might
not have a GT pointer in some scenarios (review feedback from Michal W).
Split definitions into separate header (review feedback from Jani).
Convert all intel_gt*.c files.
v4: Re-order some macro definitions (Andi S), update (c) date (Tvrtko)

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230111200429.2139084-2-John.C.Harrison@Intel.com