cpufreq: mediatek: change to regulator_get_optional

For new mediatek chip mt8183,
cci and little cluster share the same buck,
so need to modify the attribute of regulator from exclusive to optional
Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/mediatek-cpufreq.c

@@ -338,7 +338,7 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
 		goto out_free_resources;
 	}
 
-	proc_reg = regulator_get_exclusive(cpu_dev, "proc");
+	proc_reg = regulator_get_optional(cpu_dev, "proc");
 	if (IS_ERR(proc_reg)) {
 		if (PTR_ERR(proc_reg) == -EPROBE_DEFER)
 			pr_warn("proc regulator for cpu%d not ready, retry.\n",