ASoC: SOF: sof-client: fix build when only IPC4 is selected

ASoC: SOF: sof-client: fix build when only IPC4 is selected

When IPC3 is not selected, sof-client.c still makes a hard-coded
reference to an IPC3-specific function:

ERROR: modpost: "sof_ipc3_do_rx_work" [sound/soc/sof/snd-sof.ko]
undefined!

Fix by making the code conditional.

Closes: https://github.com/thesofproject/linux/issues/4581
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Curtis Malainey <cujomalainey@chromium.org>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20231006084041.18100-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>