drm/vboxvideo/modesetting: Provide function names for prototype headers

Fixes the following W=1 kernel build warning(s):

drivers/gpu/drm/vboxvideo/modesetting.c:11: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
drivers/gpu/drm/vboxvideo/modesetting.c:54: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
drivers/gpu/drm/vboxvideo/modesetting.c:87: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Hans de Goede <hdegoede@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602143300.2330146-27-lee.jones@linaro.org

drm/vboxvideo: Move the vboxvideo driver out of staging

The vboxvideo driver has been converted to the atomic modesetting API
and all FIXME and TODO items have been fixed, so it is time to move it out
of staging.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190304164724.10210-4-hdegoede@redhat.com