staging: android: ion: Avoid calling free_duped_table() twice

Currently, the duplicated sg table is freed in the detach() and
the error path of map_dma_buf() ion's dma_buf_ops.

If a call to dma_buf_map_attachment() fails, the importer is
expected to call dma_buf_detach() to remove the attachment. This
will result in us trying to free the duped sg table twice.

Don't call free_duped_table() in ion_map_dma_buf() to avoid this.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>