dma-buf: add the name field to the table header

'cat /sys/kernel/debug/dma_buf/bufinfo' will print the Dma-buf
Objects' information when the CONFIG_DEBUG_FS=y.
However, the printed table header information does not contain
the name field. So we need to add the name field to the table
header and use the '<none>' to replace the empty buf_obj->name.

Signed-off-by: Yuanzheng Song <songyuanzheng@huawei.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428063924.3570409-1-songyuanzheng@huawei.com