drm/vram: remove unused declaration

drm/vram: remove unused declaration

Commit b0e40e080522 ("vram: Have VRAM MM call GEM VRAM functions directly")
removed this.

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: b0e40e080522 ("drm/vram: Have VRAM MM call GEM VRAM functions directly")
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20191126184339.337-1-gurchetansingh@chromium.org