soundwire: add static port mapping support

Some of the SoundWire device ports are statically mapped to Controller
ports during design, however there is no way to expose this information
to the controller. Controllers like Qualcomm ones use this info to setup
static bandwidth parameters for those ports.

A generic port allocation is not possible in this cases!
So this patch adds a new member m_port_map to struct sdw_slave to expose
this static map.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210315165650.13392-2-srinivas.kandagatla@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>