drm/vmwgfx: Don't overwrite KMS surface dirty tracker

We were overwriting the surface's dirty tracker here causing a memory leak.

Reported-by: Mika Penttilä <[email protected]>
Closes: https://lore.kernel.org/dri-devel/[email protected]/
Fixes: 9655441 ("drm/vmwgfx: Refactor cursor handling")
Signed-off-by: Ian Forbes <[email protected]>
Reviewed-by: Maaz Mombasawala <[email protected]>
Signed-off-by: Zack Rusin <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: en4bz

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -771,7 +771,8 @@ static struct drm_framebuffer *vmw_kms_fb_create(struct drm_device *dev,
 		ret = vmw_bo_dirty_add(bo);
 		if (!ret && surface && surface->res.func->dirty_alloc) {
 			surface->res.coherent = true;
-			ret = surface->res.func->dirty_alloc(&surface->res);
+			if (surface->res.dirty == NULL)
+				ret = surface->res.func->dirty_alloc(&surface->res);
 		}
 		ttm_bo_unreserve(&bo->tbo);
 	}