drm_print: interpose drm_*dbg with forwarding macros

change drm_dev_dbg & drm_dbg to macros, which forward to the renamed
functions (with __ prefix added).

Those functions sit below the categorized layer of macros implementing
the DRM debug.category API, and implement most of it.  These are good
places to insert dynamic-debug jump-label mechanics, which will allow
DRM to avoid the runtime cost of drm_debug_enabled().

no functional changes.

memory cost baseline: (unchanged)
bash-5.1# drms_load
[    9.220389] dyndbg:   1 debug prints in module drm
[    9.224426] ACPI: bus type drm_connector registered
[    9.302192] dyndbg:   2 debug prints in module ttm
[    9.305033] dyndbg:   8 debug prints in module video
[    9.627563] dyndbg: 127 debug prints in module i915
[    9.721505] AMD-Vi: AMD IOMMUv2 functionality not available on this system - This is not a bug.
[   10.091345] dyndbg: 2196 debug prints in module amdgpu
[   10.106589] [drm] amdgpu kernel modesetting enabled.
[   10.107270] amdgpu: CRAT table not found
[   10.107926] amdgpu: Virtual CRAT table created for CPU
[   10.108398] amdgpu: Topology: Add CPU node
[   10.168507] dyndbg:   3 debug prints in module wmi
[   10.329587] dyndbg:   3 debug prints in module nouveau
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220912052852.1123868-4-jim.cromie@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/drm_print.c

@@ -279,7 +279,7 @@ void drm_dev_printk(const struct device *dev, const char *level,
 }
 EXPORT_SYMBOL(drm_dev_printk);
 
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 		   const char *format, ...)
 {
 	struct va_format vaf;
@@ -301,9 +301,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 
 	va_end(args);
 }
-EXPORT_SYMBOL(drm_dev_dbg);
+EXPORT_SYMBOL(__drm_dev_dbg);
 
-void __drm_dbg(enum drm_debug_category category, const char *format, ...)
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -320,7 +320,7 @@ void __drm_dbg(enum drm_debug_category category, const char *format, ...)
 
 	va_end(args);
 }
-EXPORT_SYMBOL(__drm_dbg);
+EXPORT_SYMBOL(___drm_dbg);
 
 void __drm_err(const char *format, ...)
 {

include/drm/drm_print.h

@@ -335,7 +335,7 @@ __printf(3, 4)
 void drm_dev_printk(const struct device *dev, const char *level,
 		    const char *format, ...);
 __printf(3, 4)
-void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
+void __drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 		 const char *format, ...);
 
 /**
@@ -384,6 +384,9 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
 	}								\
 })
 
+#define drm_dev_dbg(dev, cat, fmt, ...)				\
+	__drm_dev_dbg(dev, cat, fmt, ##__VA_ARGS__)
+
 /**
  * DRM_DEV_DEBUG() - Debug output for generic drm code
  *
@@ -485,10 +488,12 @@ void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
  */
 
 __printf(2, 3)
-void __drm_dbg(enum drm_debug_category category, const char *format, ...);
+void ___drm_dbg(enum drm_debug_category category, const char *format, ...);
 __printf(1, 2)
 void __drm_err(const char *format, ...);
 
+#define __drm_dbg(fmt, ...)		___drm_dbg(fmt, ##__VA_ARGS__)
+
 /* Macros to make printk easier */
 
 #define _DRM_PRINTK(once, level, fmt, ...)				\