ALSA: hda: intel-sdw-acpi: harden detection of controller

The existing code currently sets a pointer to an ACPI handle before
checking that it's actually a SoundWire controller. This can lead to
issues where the graph walk continues and eventually fails, but the
pointer was set already.

This patch changes the logic so that the information provided to
the caller is set when a controller is found.
Reviewed-by: NPéter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: NLibin Yang <libin.yang@intel.com>
Signed-off-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: NBard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20211221010817.23636-2-yung-chuan.liao@linux.intel.comSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/hda/intel-sdw-acpi.c

@@ -132,8 +132,6 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 		return AE_NOT_FOUND;
 	}
 
-	info->handle = handle;
-
 	/*
 	 * On some Intel platforms, multiple children of the HDAS
 	 * device can be found, but only one of them is the SoundWire
@@ -144,6 +142,9 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 	if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
 		return AE_OK; /* keep going */
 
+	/* found the correct SoundWire controller */
+	info->handle = handle;
+
 	/* device found, stop namespace walk */
 	return AE_CTRL_TERMINATE;
 }