drm/vmwgfx: Implement create_handle on drm_framebuffer_funcs

The fb handle code assumes it deals with GEM objects. Because vmwgfx
buffer objects were not actually GEM objects we were not able to
implement that interface. Now that vmwgfx supports GEM buffer objects
we can trivially implement create_handle for buffer object backed
framebuffers.
Among others this gets IGT's kms_getfb test passing.

Signed-off-by: Zack Rusin <[e-mail]>
Reviewed-by: Martin Krastev <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

···
  * Buffer-object framebuffer code
  */
 
+static int vmw_framebuffer_bo_create_handle(struct drm_framebuffer *fb,
+					    struct drm_file *file_priv,
+					    unsigned int *handle)
+{
+	struct vmw_framebuffer_bo *vfbd =
+			vmw_framebuffer_to_vfbd(fb);
+
+	return drm_gem_handle_create(file_priv, &vfbd->buffer->base.base, handle);
+}
+
 static void vmw_framebuffer_bo_destroy(struct drm_framebuffer *framebuffer)
 {
 	struct vmw_framebuffer_bo *vfbd =
···
 }
 
 static const struct drm_framebuffer_funcs vmw_framebuffer_bo_funcs = {
+	.create_handle = vmw_framebuffer_bo_create_handle,
 	.destroy = vmw_framebuffer_bo_destroy,
 	.dirty = vmw_framebuffer_bo_dirty_ext,
 };