libdrm_radeon: Optimize copy of table to cs buffer with specialized call.

Using this call in OUT_BATCH_TABLE reduces radeonEmitState cpu usage from
9% to 5% and emit_vpu goes from 7% to 1.5%. I did use calgrind to profile
gears for cpu hotspots with r500 card.

Signed-off-by: Pauli Nieminen <suokkos@gmail.com>