drm/panic: Restrict graphical logo handling to built-in

When CONFIG_DRM_PANIC=y, but CONFIG_DRM=m:

    ld: drivers/gpu/drm/drm_panic.o: in function `drm_panic_setup_logo':
    drivers/gpu/drm/drm_panic.c:99: multiple definition of `init_module'; drivers/gpu/drm/drm_drv.o:drivers/gpu/drm/drm_drv.c:1079: first defined here

Fix this by restricting the graphical logo handling and its
device_initcall() to the built-in case.  Logos are freed during late
kernel initialization, so they are no longer available at module load
time anyway.

Fixes: 294bbd1f ("drm/panic: Add support for drawing a monochrome graphical logo")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406261341.GYsbLpN1-lkp@intel.com/Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4009fca99a7c05f617cc9899c6d0a5748415595d.1719391132.git.geert+renesas@glider.be

drivers/gpu/drm/drm_panic.c

@@ -91,7 +91,7 @@ static const struct drm_panic_line logo_ascii[] = {
 	PANIC_LINE(" \\___)=(___/"),
 };
 
-#ifdef CONFIG_LOGO
+#if defined(CONFIG_LOGO) && !defined(MODULE)
 static const struct linux_logo *logo_mono;
 
 static int drm_panic_setup_logo(void)