soundwire: export sdw_compare_devid, sdw_extract_slave_id and sdw_slave_add

Exporting these three functions makes sense as it can be used by
other controllers like Qualcomm during auto-enumeration!

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210330144719.13284-8-srinivas.kandagatla@linaro.org


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