ASoC: codecs: wsa881x: Correct Soundwire ports mask

Device has up to WSA881X_MAX_SWR_PORTS number of ports and the array
assigned to prop.sink_dpn_prop has 0..WSA881X_MAX_SWR_PORTS-1 elements.
On the other hand, GENMASK(high, low) creates an inclusive mask between
<high, low>, so we need the mask from 0 up to WSA881X_MAX_SWR_PORTS-1.

Theoretically, too wide mask could cause an out of bounds read in
sdw_get_slave_dpn_prop() in stream.c, however only in the case of buggy
driver, e.g. adding incorrect number of ports via
sdw_stream_add_slave().

Fixes: a0aab9e1 ("ASoC: codecs: add wsa881x amplifier support")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20240726-asoc-wcd-wsa-swr-ports-genmask-v1-4-d4d7a8b56f05@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wsa881x.c

@@ -1152,7 +1152,7 @@ static int wsa881x_probe(struct sdw_slave *pdev,
 	wsa881x->sconfig.frame_rate = 48000;
 	wsa881x->sconfig.direction = SDW_DATA_DIR_RX;
 	wsa881x->sconfig.type = SDW_STREAM_PDM;
-	pdev->prop.sink_ports = GENMASK(WSA881X_MAX_SWR_PORTS, 0);
+	pdev->prop.sink_ports = GENMASK(WSA881X_MAX_SWR_PORTS - 1, 0);
 	pdev->prop.sink_dpn_prop = wsa_sink_dpn_prop;
 	pdev->prop.scp_int1_mask = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY;
 	pdev->prop.clk_stop_mode1 = true;