drm/xe/bo: Don't include the CCS metadata in the dma-buf sg-table

commit 449bcd5 upstream.

Some Xe bos are allocated with extra backing-store for the CCS
metadata. It's never been the intention to share the CCS metadata
when exporting such bos as dma-buf. Don't include it in the
dma-buf sg-table.

Fixes: dd08ebf ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: <stable@vger.kernel.org> # v6.8+
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Link: https://patch.msgid.link/20251209204920.224374-1-thomas.hellstrom@linux.intel.com
(cherry picked from commit a4ebfb9)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Thomas Hellström

drivers/gpu/drm/xe/xe_dma_buf.c

@@ -113,7 +113,7 @@ static struct sg_table *xe_dma_buf_map(struct dma_buf_attachment *attach,
 	case XE_PL_TT:
 		sgt = drm_prime_pages_to_sg(obj->dev,
 					    bo->ttm.ttm->pages,
-					    bo->ttm.ttm->num_pages);
+					    obj->size >> PAGE_SHIFT);
 		if (IS_ERR(sgt))
 			return sgt;