PM / devfreq: tegra: Replace readl-writel with relaxed versions

There is no need to insert memory barrier on each readl/writel
invocation, hence use the relaxed versions.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/tegra-devfreq.c

@@ -179,23 +179,23 @@ static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
 
 static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
 {
-	return readl(tegra->regs + offset);
+	return readl_relaxed(tegra->regs + offset);
 }
 
 static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
 {
-	writel(val, tegra->regs + offset);
+	writel_relaxed(val, tegra->regs + offset);
 }
 
 static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
 {
-	return readl(dev->regs + offset);
+	return readl_relaxed(dev->regs + offset);
 }
 
 static void device_writel(struct tegra_devfreq_device *dev, u32 val,
 			  u32 offset)
 {
-	writel(val, dev->regs + offset);
+	writel_relaxed(val, dev->regs + offset);
 }
 
 static unsigned long do_percent(unsigned long val, unsigned int pct)