accel/qaic: Undo slicing setup done in qaic_attach_slicing_bo()

qaic_attach_slicing_bo() updates slicing config on BO. Use the existing
function qaic_free_slices_bo() to remove slicing config done in
qaic_attach_slicing_bo().

Use qaic_free_slices_bo() to cleanup release_dbc()

This would be helpful when we introduce a new IOCTL to detach slicing
configuration onto a BO.

Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901172247.11410-5-quic_jhugo@quicinc.com