[PATCH v3 14/19] drm_print: fix stale macro-name in comment

[Jim Cromie <jim.cromie@gmail.com>]

Cited commit uses stale macro name, fix this, and explain better.

When DRM_USE_DYNAMIC_DEBUG=y, DYNDBG_CLASSMAP_DEFINE() maps DRM_UT_*
onto BITs in drm.debug.  This still uses enum drm_debug_category, but
it is somewhat indirect, with the ordered set of DRM_UT_* enum-vals.
This requires that the macro args: DRM_UT_* list must be kept in sync
and in order.

Fixes: f158936b60a7 ("drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
. emphasize ABI non-change despite enum val change - Jani Nikula
. reorder to back of patchset to follow API name changes.
---
 include/drm/drm_print.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 6a27e8f26770..7695ba31b3a4 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -276,7 +276,10 @@ static inline struct drm_printer drm_err_printer(const char *prefix)
  *
  */
 enum drm_debug_category {
-	/* These names must match those in DYNAMIC_DEBUG_CLASSBITS */
+	/*
+	 * Keep DYNDBG_CLASSMAP_DEFINE args in sync with changes here,
+	 * the enum-values define BIT()s in drm.debug, so are ABI.
+	 */
 	/**
 	 * @DRM_UT_CORE: Used in the generic drm code: drm_ioctl.c, drm_mm.c,
 	 * drm_memory.c, ...
-- 
2.39.1