soc: mediatek: mtk-dvfsrc: Change error check for DVFSRCv4 START cmd

In preparation for adding support for DVFSRC Version 4, change the
error check for the MTK_SIP_DVFSRC_START command in the probe
function to error out only if BIT(0) is set: this is still valid
for the previous DVFSRC versions, as those always set this bit in
a fail reply anyway.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Author: AngeloGioacchino Del Regno

drivers/soc/mediatek/mtk-dvfsrc.c

@@ -440,7 +440,7 @@ static int mtk_dvfsrc_probe(struct platform_device *pdev)
 	/* Everything is set up - make it run! */
 	arm_smccc_smc(MTK_SIP_DVFSRC_VCOREFS_CONTROL, MTK_SIP_DVFSRC_START,
 		      0, 0, 0, 0, 0, 0, &ares);
-	if (ares.a0)
+	if (ares.a0 & BIT(0))
 		return dev_err_probe(&pdev->dev, -EINVAL, "Cannot start DVFSRC: %lu\n", ares.a0);
 
 	return 0;