Revert "drm/sched: Define pr_fmt() for DRM using pr_*()"

From Jani:
The drm_print.[ch] facilities use very few pr_*() calls directly. The
users of pr_*() calls do not necessarily include <drm/drm_print.h> at
all, and really don't have to.

Even the ones that do include it, usually have <linux/...> includes
first, and <drm/...> includes next. Notably, <linux/kernel.h> includes
<linux/printk.h>.

And, of course, <linux/printk.h> defines pr_fmt() itself if not already
defined.

No, it's encouraged not to use pr_*() at all, and prefer drm device
based logging, or device based logging.

This reverts commit 36245bd02e.

Signed-off-by: Luben Tuikov <ltuikov89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/878r75wzm9.fsf@intel.com
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231111024130.11464-2-ltuikov89@gmail.com

include/drm/drm_print.h

@@ -26,20 +26,6 @@
 #ifndef DRM_PRINT_H_
 #define DRM_PRINT_H_
 
-/* Define this before including linux/printk.h, so that the format
- * string in pr_*() macros is correctly set for DRM. If a file wants
- * to define this to something else, it should do so before including
- * this header file.
- *
- * It is encouraged code using pr_err() to prefix their format with
- * the string "*ERROR* ", to make it easier to scan kernel logs. For
- * instance,
- *   pr_err("*ERROR* <the rest of your format string here>", args).
- */
-#ifndef pr_fmt
-#define pr_fmt(fmt) "[drm] " fmt
-#endif
-
 #include <linux/compiler.h>
 #include <linux/printk.h>
 #include <linux/seq_file.h>