rs: make use of xxx_tiling to determine multi pipe usage

We can detect via source and dest tiling if we need to use
multi pipes. So we can get rid of the extra tow mutli
variables in rs_state.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
driver: add support for multi tiled formats

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