ASoC: wm_adsp: Support DSPs that don't require firmware download

When a DSP can self-boot from ROM it is not necessary to download
firmware - when the DSP has the wmfw_optional flag set not finding a
wmfw firmware file is a successful outcome and not an error condition.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/167931140130.26.15590061696793062038@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm_adsp.c

@@ -850,6 +850,9 @@ static int wm_adsp_request_firmware_files(struct wm_adsp *dsp,
 		return 0;
 	}
 
+	if (dsp->wmfw_optional)
+		return 0;
+
 	adsp_err(dsp, "Failed to request firmware <%s>%s-%s-%s<-%s<%s>>.wmfw\n",
 		 cirrus_dir, dsp->part, dsp->fwf_name, wm_adsp_fw[dsp->fw].file,
 		 system_name, asoc_component_prefix);

sound/soc/codecs/wm_adsp.h

@@ -34,6 +34,7 @@ struct wm_adsp {
 	unsigned int sys_config_size;
 
 	int fw;
+	bool wmfw_optional;
 
 	struct work_struct boot_work;
 	int (*pre_run)(struct wm_adsp *dsp);