add basic support for ETNA_BO_DMA

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
add vivante_gem_paddr_locked(..)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
set VIVS_FE_COMMAND_ADDRESS to physical address of bo (ETNA_BO_DMA)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>