drm: remove unused header gma_drm.h

gma_drm.h has become an empty, unused header. Remove.

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240408104230.3191827-1-jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

include/drm/gma_drm.h

-/* SPDX-License-Identifier: GPL-2.0-only */
-/**************************************************************************
- * Copyright (c) 2007-2011, Intel Corporation.
- * All Rights Reserved.
- * Copyright (c) 2008, Tungsten Graphics Inc.  Cedar Park, TX., USA.
- * All Rights Reserved.
- *
- **************************************************************************/
-
-#ifndef _GMA_DRM_H_
-#define _GMA_DRM_H_
-
-#endif