clk: add static qualifier to local functions

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/clk/clk_rk3036.c

@@ -314,7 +314,7 @@ static ulong rk3036_clk_set_rate(struct udevice *dev, ulong rate)
 	return 0;
 }
 
-ulong rk3036_set_periph_rate(struct udevice *dev, int periph, ulong rate)
+static ulong rk3036_set_periph_rate(struct udevice *dev, int periph, ulong rate)
 {
 	struct rk3036_clk_priv *priv = dev_get_priv(dev);
 	ulong new_rate;

drivers/clk/clk_rk3288.c

@@ -508,7 +508,7 @@ static ulong rockchip_spi_set_clk(struct rk3288_cru *cru, uint clk_general_rate,
 	return rockchip_spi_get_clk(cru, clk_general_rate, periph);
 }
 
-ulong rk3288_set_periph_rate(struct udevice *dev, int periph, ulong rate)
+static ulong rk3288_set_periph_rate(struct udevice *dev, int periph, ulong rate)
 {
 	struct rk3288_clk_priv *priv = dev_get_priv(dev);
 	ulong new_rate;

drivers/clk/clk_sandbox.c

@@ -32,7 +32,7 @@ static ulong sandbox_clk_set_rate(struct udevice *dev, ulong rate)
 	return 0;
 }
 
-ulong sandbox_get_periph_rate(struct udevice *dev, int periph)
+static ulong sandbox_get_periph_rate(struct udevice *dev, int periph)
 {
 	struct sandbox_clk_priv *priv = dev_get_priv(dev);
 
@@ -41,7 +41,8 @@ ulong sandbox_get_periph_rate(struct udevice *dev, int periph)
 	return priv->periph_rate[periph];
 }
 
-ulong sandbox_set_periph_rate(struct udevice *dev, int periph, ulong rate)
+static ulong sandbox_set_periph_rate(struct udevice *dev, int periph,
+				     ulong rate)
 {
 	struct sandbox_clk_priv *priv = dev_get_priv(dev);
 	ulong old_rate;