drm/panic: Remove useless export symbols

drm_panic_[un]register() are called only from the core drm, so there
is no need to export them.
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240807134902.458669-3-jfalempe@redhat.com

drivers/gpu/drm/drm_panic.c

@@ -752,7 +752,6 @@ void drm_panic_register(struct drm_device *dev)
 	if (registered_plane)
 		drm_info(dev, "Registered %d planes with drm panic\n", registered_plane);
 }
-EXPORT_SYMBOL(drm_panic_register);
 
 /**
  * drm_panic_unregister()
@@ -771,4 +770,3 @@ void drm_panic_unregister(struct drm_device *dev)
 		kmsg_dump_unregister(&plane->kmsg_panic);
 	}
 }
-EXPORT_SYMBOL(drm_panic_unregister);